From 11f29b1231620cb07e2a91b1e0d143ade8bf3c58 Mon Sep 17 00:00:00 2001
From: whitequark <whitequark@whitequark.org>
Date: Fri, 6 Nov 2015 11:40:12 +0300
Subject: [PATCH] Replace NameStr with std::string.

This removes the arbitrary 64 byte restriction (which effectively
limits us to as little as 16 Unicode characters with CJK encodings),
makes classes smaller, and is easier to use.

As a consequence of making the length of all ex-NameStr fields
unbounded, all functions that returned a buffer derived from those
were changed to return std::string. Then, functions that are
contextually similar to the ones described above were changed
to return std::string. Then, functions that now happened to mostly
take an std::string argument converted to a C string were changed
to accept std::string.

This has produced a bit of churn, but is probably for the better.
---
 src/clipboard.cpp      | 20 ++++++------
 src/cocoa/cocoamain.mm |  8 ++---
 src/confscreen.cpp     | 43 ++++++++++++------------
 src/constraint.cpp     |  7 ++--
 src/describescreen.cpp | 52 +++++++++++++++--------------
 src/drawconstraint.cpp | 36 ++++++++++----------
 src/drawentity.cpp     | 10 +++---
 src/dsc.h              | 10 ------
 src/exportvector.cpp   | 10 +++---
 src/expr.cpp           | 40 +++++++----------------
 src/expr.h             |  6 ++--
 src/file.cpp           | 32 +++++++++---------
 src/group.cpp          | 30 ++++++++---------
 src/gtk/gtkmain.cpp    |  6 ++--
 src/mouse.cpp          | 26 +++++++--------
 src/request.cpp        | 11 +++----
 src/sketch.h           | 36 ++++++++++----------
 src/solvespace.cpp     | 18 +++-------
 src/solvespace.h       | 19 +++++++----
 src/style.cpp          | 74 ++++++++++++++++++------------------------
 src/textscreens.cpp    | 69 ++++++++++++++++++---------------------
 src/textwin.cpp        |  4 +--
 src/ttf.cpp            | 13 +++-----
 src/ui.h               |  2 +-
 src/util.cpp           | 19 +++++++++++
 src/view.cpp           | 29 ++++++++---------
 src/win32/w32main.cpp  |  8 ++---
 27 files changed, 297 insertions(+), 341 deletions(-)

diff --git a/src/clipboard.cpp b/src/clipboard.cpp
index 031002aa..4855f2ce 100644
--- a/src/clipboard.cpp
+++ b/src/clipboard.cpp
@@ -86,8 +86,8 @@ void GraphicsWindow::CopySelection(void) {
         cr.type         = req;
         cr.extraPoints  = e->extraPoints;
         cr.style        = e->style;
-        cr.str.strcpy(    e->str.str);
-        cr.font.strcpy(   e->font.str);
+        cr.str          = e->str;
+        cr.font         = e->font;
         cr.construction = e->construction;
         {for(int i = 0; i < pts; i++) {
             Vector pt = SK.GetEntity(e->point[i])->PointGetNum();
@@ -133,8 +133,8 @@ void GraphicsWindow::PasteClipboard(Vector trans, double theta, double scale) {
         Request *r = SK.GetRequest(hr);
         r->extraPoints  = cr->extraPoints;
         r->style        = cr->style;
-        r->str.strcpy(    cr->str.str);
-        r->font.strcpy(   cr->font.str);
+        r->str          = cr->str;
+        r->font         = cr->font;
         r->construction = cr->construction;
         // Need to regen to get the right number of points, if extraPoints
         // changed.
@@ -374,14 +374,14 @@ void TextWindow::ShowPasteTransformed(void) {
         shown.paste.theta*180/PI,
         &ScreenChangePasteTransformed);
     Printf(false, "%Ba   %Ftabout pt%E  (%s, %s, %s) %Fl%Lo%f[use selected]%E",
-            SS.MmToString(shown.paste.origin.x),
-            SS.MmToString(shown.paste.origin.y),
-            SS.MmToString(shown.paste.origin.z),
+            SS.MmToString(shown.paste.origin.x).c_str(),
+            SS.MmToString(shown.paste.origin.y).c_str(),
+            SS.MmToString(shown.paste.origin.z).c_str(),
         &ScreenPasteTransformed);
     Printf(false, "%Bd   %Fttranslate%E (%s, %s, %s) %Fl%Lt%f[use selected]%E",
-            SS.MmToString(shown.paste.trans.x),
-            SS.MmToString(shown.paste.trans.y),
-            SS.MmToString(shown.paste.trans.z),
+            SS.MmToString(shown.paste.trans.x).c_str(),
+            SS.MmToString(shown.paste.trans.y).c_str(),
+            SS.MmToString(shown.paste.trans.z).c_str(),
         &ScreenPasteTransformed);
     Printf(false, "%Ba   %Ftscale%E     %@ %Fl%Ls%f[change]%E",
         shown.paste.scale,
diff --git a/src/cocoa/cocoamain.mm b/src/cocoa/cocoamain.mm
index be30e63f..4779ef7d 100644
--- a/src/cocoa/cocoamain.mm
+++ b/src/cocoa/cocoamain.mm
@@ -487,8 +487,8 @@ bool FullScreenIsActive(void) {
     return [GWDelegate isFullscreen];
 }
 
-void ShowGraphicsEditControl(int x, int y, char *str) {
-    [GWView startEditing:[NSString stringWithUTF8String:str]
+void ShowGraphicsEditControl(int x, int y, const std::string &str) {
+    [GWView startEditing:[NSString stringWithUTF8String:str.c_str()]
             at:(NSPoint){(CGFloat)x, (CGFloat)y}];
 }
 
@@ -1010,8 +1010,8 @@ void SetMousePointerToHand(bool is_hand) {
     [TWView setCursorHand:is_hand];
 }
 
-void ShowTextEditControl(int x, int y, char *str) {
-    return [TWView startEditing:[NSString stringWithUTF8String:str]
+void ShowTextEditControl(int x, int y, const std::string &str) {
+    return [TWView startEditing:[NSString stringWithUTF8String:str.c_str()]
                    at:(NSPoint){(CGFloat)x, (CGFloat)y}];
 }
 
diff --git a/src/confscreen.cpp b/src/confscreen.cpp
index 135998d2..1ea254e8 100644
--- a/src/confscreen.cpp
+++ b/src/confscreen.cpp
@@ -137,30 +137,30 @@ void TextWindow::ScreenChangeCanvasSize(int link, uint32_t v) {
 }
 
 void TextWindow::ScreenChangeGCodeParameter(int link, uint32_t v) {
-    char buf[1024] = "";
+    std::string buf;
     int row = 93;
     switch(link) {
         case 'd':
             SS.TW.edit.meaning = EDIT_G_CODE_DEPTH;
-            strcpy(buf, SS.MmToString(SS.gCode.depth));
+            buf += SS.MmToString(SS.gCode.depth);
             row += 0;
             break;
 
         case 's':
             SS.TW.edit.meaning = EDIT_G_CODE_PASSES;
-            sprintf(buf, "%d", SS.gCode.passes);
+            buf += std::to_string(SS.gCode.passes);
             row += 2;
             break;
 
         case 'F':
             SS.TW.edit.meaning = EDIT_G_CODE_FEED;
-            strcpy(buf, SS.MmToString(SS.gCode.feed));
+            buf += SS.MmToString(SS.gCode.feed);
             row += 4;
             break;
 
         case 'P':
             SS.TW.edit.meaning = EDIT_G_CODE_PLUNGE_FEED;
-            strcpy(buf, SS.MmToString(SS.gCode.plungeFeed));
+            buf += SS.MmToString(SS.gCode.plungeFeed);
             row += 6;
             break;
     }
@@ -168,10 +168,7 @@ void TextWindow::ScreenChangeGCodeParameter(int link, uint32_t v) {
 }
 
 void TextWindow::ScreenChangeAutosaveInterval(int link, uint32_t v) {
-    char str[1024];
-    sprintf(str, "%d", SS.autosaveInterval);
-
-    SS.TW.ShowEditControl(111, 3, str);
+    SS.TW.ShowEditControl(111, 3, std::to_string(SS.autosaveInterval));
     SS.TW.edit.meaning = EDIT_AUTOSAVE_INTERVAL;
 }
 
@@ -218,13 +215,13 @@ void TextWindow::ShowConfiguration(void) {
         &ScreenChangeCameraTangent, 0);
     Printf(false, "%Ft snap grid spacing%E");
     Printf(false, "%Ba   %s %Fl%Ll%f%D[change]%E",
-        SS.MmToString(SS.gridSpacing),
+        SS.MmToString(SS.gridSpacing).c_str(),
         &ScreenChangeGridSpacing, 0);
     Printf(false, "%Ft digits after decimal point to show%E");
     Printf(false, "%Ba   %d %Fl%Ll%f%D[change]%E (e.g. '%s')",
         SS.UnitDigitsAfterDecimal(),
         &ScreenChangeDigitsAfterDecimal, 0,
-        SS.MmToString(SS.StringToMm("1.23456789")));
+        SS.MmToString(SS.StringToMm("1.23456789")).c_str());
 
     Printf(false, "");
     Printf(false, "%Ft export scale factor (1:1=mm, 1:25.4=inch)");
@@ -233,7 +230,7 @@ void TextWindow::ShowConfiguration(void) {
         &ScreenChangeExportScale, 0);
     Printf(false, "%Ft cutter radius offset (0=no offset) ");
     Printf(false, "%Ba   %s %Fl%Ll%f%D[change]%E",
-        SS.MmToString(SS.exportOffset),
+        SS.MmToString(SS.exportOffset).c_str(),
         &ScreenChangeExportOffset, 0);
 
     Printf(false, "");
@@ -264,35 +261,35 @@ void TextWindow::ShowConfiguration(void) {
     if(SS.exportCanvasSizeAuto) {
         Printf(false, "%Ft (by margins around exported geometry)");
         Printf(false, "%Ba%Ft   left:   %Fd%s %Fl%Ll%f%D[change]%E",
-            SS.MmToString(SS.exportMargin.left), &ScreenChangeCanvasSize, 0);
+            SS.MmToString(SS.exportMargin.left).c_str(), &ScreenChangeCanvasSize, 0);
         Printf(false, "%Bd%Ft   right:  %Fd%s %Fl%Ll%f%D[change]%E",
-            SS.MmToString(SS.exportMargin.right), &ScreenChangeCanvasSize, 1);
+            SS.MmToString(SS.exportMargin.right).c_str(), &ScreenChangeCanvasSize, 1);
         Printf(false, "%Ba%Ft   bottom: %Fd%s %Fl%Ll%f%D[change]%E",
-            SS.MmToString(SS.exportMargin.bottom), &ScreenChangeCanvasSize, 2);
+            SS.MmToString(SS.exportMargin.bottom).c_str(), &ScreenChangeCanvasSize, 2);
         Printf(false, "%Bd%Ft   top:    %Fd%s %Fl%Ll%f%D[change]%E",
-            SS.MmToString(SS.exportMargin.top), &ScreenChangeCanvasSize, 3);
+            SS.MmToString(SS.exportMargin.top).c_str(), &ScreenChangeCanvasSize, 3);
     } else {
         Printf(false, "%Ft (by absolute dimensions and offsets)");
         Printf(false, "%Ba%Ft   width:    %Fd%s %Fl%Ll%f%D[change]%E",
-            SS.MmToString(SS.exportCanvas.width), &ScreenChangeCanvasSize, 10);
+            SS.MmToString(SS.exportCanvas.width).c_str(), &ScreenChangeCanvasSize, 10);
         Printf(false, "%Bd%Ft   height:   %Fd%s %Fl%Ll%f%D[change]%E",
-            SS.MmToString(SS.exportCanvas.height), &ScreenChangeCanvasSize, 11);
+            SS.MmToString(SS.exportCanvas.height).c_str(), &ScreenChangeCanvasSize, 11);
         Printf(false, "%Ba%Ft   offset x: %Fd%s %Fl%Ll%f%D[change]%E",
-            SS.MmToString(SS.exportCanvas.dx), &ScreenChangeCanvasSize, 12);
+            SS.MmToString(SS.exportCanvas.dx).c_str(), &ScreenChangeCanvasSize, 12);
         Printf(false, "%Bd%Ft   offset y: %Fd%s %Fl%Ll%f%D[change]%E",
-            SS.MmToString(SS.exportCanvas.dy), &ScreenChangeCanvasSize, 13);
+            SS.MmToString(SS.exportCanvas.dy).c_str(), &ScreenChangeCanvasSize, 13);
     }
 
     Printf(false, "");
     Printf(false, "%Ft exported g code parameters");
     Printf(false, "%Ba%Ft   depth:     %Fd%s %Fl%Ld%f[change]%E",
-        SS.MmToString(SS.gCode.depth), &ScreenChangeGCodeParameter);
+        SS.MmToString(SS.gCode.depth).c_str(), &ScreenChangeGCodeParameter);
     Printf(false, "%Bd%Ft   passes:    %Fd%d %Fl%Ls%f[change]%E",
         SS.gCode.passes, &ScreenChangeGCodeParameter);
     Printf(false, "%Ba%Ft   feed:      %Fd%s %Fl%LF%f[change]%E",
-        SS.MmToString(SS.gCode.feed), &ScreenChangeGCodeParameter);
+        SS.MmToString(SS.gCode.feed).c_str(), &ScreenChangeGCodeParameter);
     Printf(false, "%Bd%Ft   plunge fd: %Fd%s %Fl%LP%f[change]%E",
-        SS.MmToString(SS.gCode.plungeFeed), &ScreenChangeGCodeParameter);
+        SS.MmToString(SS.gCode.plungeFeed).c_str(), &ScreenChangeGCodeParameter);
 
     Printf(false, "");
     Printf(false, "  %Fd%f%Ll%s  draw triangle back faces in red%E",
diff --git a/src/constraint.cpp b/src/constraint.cpp
index a672cb62..2e2ef1f0 100644
--- a/src/constraint.cpp
+++ b/src/constraint.cpp
@@ -6,9 +6,7 @@
 //-----------------------------------------------------------------------------
 #include "solvespace.h"
 
-char *Constraint::DescriptionString(void) {
-    static char ret[1024];
-
+std::string Constraint::DescriptionString(void) {
     const char *s;
     switch(type) {
         case POINTS_COINCIDENT:     s = "pts-coincident"; break;
@@ -49,8 +47,7 @@ char *Constraint::DescriptionString(void) {
         default:                    s = "???"; break;
     }
 
-    sprintf(ret, "c%03x-%s", h.v, s);
-    return ret;
+    return ssprintf("c%03x-%s", h.v, s);
 }
 
 #ifndef LIBRARY
diff --git a/src/describescreen.cpp b/src/describescreen.cpp
index 7c4e752f..c6d7f07a 100644
--- a/src/describescreen.cpp
+++ b/src/describescreen.cpp
@@ -14,7 +14,7 @@ void TextWindow::ScreenEditTtfText(int link, uint32_t v) {
     hRequest hr = { v };
     Request *r = SK.GetRequest(hr);
 
-    SS.TW.ShowEditControl(13, 10, r->str.str);
+    SS.TW.ShowEditControl(13, 10, r->str.c_str());
     SS.TW.edit.meaning = EDIT_TTF_TEXT;
     SS.TW.edit.request = hr;
 }
@@ -35,7 +35,7 @@ void TextWindow::ScreenSetTtfFont(int link, uint32_t v) {
     if(!r) return;
 
     SS.UndoRemember();
-    r->font.strcpy(SS.fonts.l.elem[i].FontFileBaseName().c_str());
+    r->font = SS.fonts.l.elem[i].FontFileBaseName();
     SS.MarkGroupDirty(r->group);
     SS.ScheduleGenerateAll();
     SS.ScheduleShowTW();
@@ -61,7 +61,9 @@ void TextWindow::DescribeSelection(void) {
         e = SK.GetEntity(gs.points == 1 ? gs.point[0] : gs.entity[0]);
 
 #define COSTR(p) \
-    SS.MmToString((p).x), SS.MmToString((p).y), SS.MmToString((p).z)
+    SS.MmToString((p).x).c_str(), \
+    SS.MmToString((p).y).c_str(), \
+    SS.MmToString((p).z).c_str()
 #define PT_AS_STR "(%Fi%s%E, %Fi%s%E, %Fi%s%E)"
 #define PT_AS_NUM "(%Fi%3%E, %Fi%3%E, %Fi%3%E)"
         switch(e->type) {
@@ -108,7 +110,7 @@ void TextWindow::DescribeSelection(void) {
                 p = p1;
                 Printf(false, "        " PT_AS_STR, COSTR(p));
                 Printf(true,  "   len = %Fi%s%E",
-                    SS.MmToString((p1.Minus(p0).Magnitude())));
+                    SS.MmToString((p1.Minus(p0).Magnitude())).c_str());
                 break;
             }
             case Entity::CUBIC_PERIODIC:
@@ -139,11 +141,11 @@ void TextWindow::DescribeSelection(void) {
                 p = SK.GetEntity(e->point[2])->PointGetNum();
                 Printf(false, "              " PT_AS_STR, COSTR(p));
                 double r = e->CircleGetRadiusNum();
-                Printf(true, "   diameter =  %Fi%s", SS.MmToString(r*2));
-                Printf(false, "     radius =  %Fi%s", SS.MmToString(r));
+                Printf(true, "   diameter =  %Fi%s", SS.MmToString(r*2).c_str());
+                Printf(false, "     radius =  %Fi%s", SS.MmToString(r).c_str());
                 double thetas, thetaf, dtheta;
                 e->ArcGetAngles(&thetas, &thetaf, &dtheta);
-                Printf(false, "    arc len =  %Fi%s", SS.MmToString(dtheta*r));
+                Printf(false, "    arc len =  %Fi%s", SS.MmToString(dtheta*r).c_str());
                 break;
             }
             case Entity::CIRCLE: {
@@ -151,8 +153,8 @@ void TextWindow::DescribeSelection(void) {
                 p = SK.GetEntity(e->point[0])->PointGetNum();
                 Printf(true,  "     center = " PT_AS_STR, COSTR(p));
                 double r = e->CircleGetRadiusNum();
-                Printf(true,  "   diameter =  %Fi%s", SS.MmToString(r*2));
-                Printf(false, "     radius =  %Fi%s", SS.MmToString(r));
+                Printf(true,  "   diameter =  %Fi%s", SS.MmToString(r*2).c_str());
+                Printf(false, "     radius =  %Fi%s", SS.MmToString(r).c_str());
                 break;
             }
             case Entity::FACE_NORMAL_PT:
@@ -169,29 +171,29 @@ void TextWindow::DescribeSelection(void) {
 
             case Entity::TTF_TEXT: {
                 Printf(false, "%FtTRUETYPE FONT TEXT%E");
-                Printf(true, "  font = '%Fi%s%E'", e->font.str);
+                Printf(true, "  font = '%Fi%s%E'", e->font.c_str());
                 if(e->h.isFromRequest()) {
                     Printf(false, "  text = '%Fi%s%E' %Fl%Ll%f%D[change]%E",
-                        e->str.str, &ScreenEditTtfText, e->h.request());
+                        e->str.c_str(), &ScreenEditTtfText, e->h.request());
                     Printf(true, "  select new font");
                     SS.fonts.LoadAll();
                     int i;
                     for(i = 0; i < SS.fonts.l.n; i++) {
                         TtfFont *tf = &(SS.fonts.l.elem[i]);
-                        if(strcmp(e->font.str, tf->FontFileBaseName().c_str())==0) {
+                        if(e->font == tf->FontFileBaseName()) {
                             Printf(false, "%Bp    %s",
                                 (i & 1) ? 'd' : 'a',
-                                tf->name.str);
+                                tf->name.c_str());
                         } else {
                             Printf(false, "%Bp    %f%D%Fl%Ll%s%E%Bp",
                                 (i & 1) ? 'd' : 'a',
                                 &ScreenSetTtfFont, i,
-                                tf->name.str,
+                                tf->name.c_str(),
                                 (i & 1) ? 'd' : 'a');
                         }
                     }
                 } else {
-                    Printf(false, "  text = '%Fi%s%E'", e->str.str);
+                    Printf(false, "  text = '%Fi%s%E'", e->str.c_str());
                 }
                 break;
             }
@@ -203,16 +205,16 @@ void TextWindow::DescribeSelection(void) {
 
         Group *g = SK.GetGroup(e->group);
         Printf(false, "");
-        Printf(false, "%FtIN GROUP%E      %s", g->DescriptionString());
+        Printf(false, "%FtIN GROUP%E      %s", g->DescriptionString().c_str());
         if(e->workplane.v == Entity::FREE_IN_3D.v) {
             Printf(false, "%FtNOT LOCKED IN WORKPLANE%E");
         } else {
             Entity *w = SK.GetEntity(e->workplane);
-            Printf(false, "%FtIN WORKPLANE%E  %s", w->DescriptionString());
+            Printf(false, "%FtIN WORKPLANE%E  %s", w->DescriptionString().c_str());
         }
         if(e->style.v) {
             Style *s = Style::Get(e->style);
-            Printf(false, "%FtIN STYLE%E      %s", s->DescriptionString());
+            Printf(false, "%FtIN STYLE%E      %s", s->DescriptionString().c_str());
         } else {
             Printf(false, "%FtIN STYLE%E      none");
         }
@@ -226,7 +228,7 @@ void TextWindow::DescribeSelection(void) {
         Vector p1 = SK.GetEntity(gs.point[1])->PointGetNum();
         Printf(false, "      " PT_AS_STR, COSTR(p1));
         double d = (p1.Minus(p0)).Magnitude();
-        Printf(true, "  d = %Fi%s", SS.MmToString(d));
+        Printf(true, "  d = %Fi%s", SS.MmToString(d).c_str());
     } else if(gs.n == 2 && gs.faces == 1 && gs.points == 1) {
         Printf(false, "%FtA POINT AND A PLANE FACE");
         Vector pt = SK.GetEntity(gs.point[0])->PointGetNum();
@@ -236,7 +238,7 @@ void TextWindow::DescribeSelection(void) {
         Vector pl = SK.GetEntity(gs.face[0])->FaceGetPointNum();
         Printf(false, "   plane thru = " PT_AS_STR, COSTR(pl));
         double dd = n.Dot(pl) - n.Dot(pt);
-        Printf(true,  "     distance = %Fi%s", SS.MmToString(dd));
+        Printf(true,  "     distance = %Fi%s", SS.MmToString(dd).c_str());
     } else if(gs.n == 3 && gs.points == 2 && gs.vectors == 1) {
         Printf(false, "%FtTWO POINTS AND A VECTOR");
         Vector p0 = SK.GetEntity(gs.point[0])->PointGetNum();
@@ -247,7 +249,7 @@ void TextWindow::DescribeSelection(void) {
         v = v.WithMagnitude(1);
         Printf(true,  "  vector = " PT_AS_NUM, CO(v));
         double d = (p1.Minus(p0)).Dot(v);
-        Printf(true,  "  proj_d = %Fi%s", SS.MmToString(d));
+        Printf(true,  "  proj_d = %Fi%s", SS.MmToString(d).c_str());
     } else if(gs.n == 2 && gs.lineSegments == 1 && gs.points == 1) {
         Entity *ln = SK.GetEntity(gs.entity[0]);
         Vector lp0 = SK.GetEntity(ln->point[0])->PointGetNum(),
@@ -258,7 +260,7 @@ void TextWindow::DescribeSelection(void) {
         Vector pp = SK.GetEntity(gs.point[0])->PointGetNum();
         Printf(true,  "     point " PT_AS_STR, COSTR(pp));
         Printf(true,  " pt-ln distance = %Fi%s%E",
-            SS.MmToString(pp.DistanceToLine(lp0, lp1.Minus(lp0))));
+            SS.MmToString(pp.DistanceToLine(lp0, lp1.Minus(lp0))).c_str());
     } else if(gs.n == 2 && gs.vectors == 2) {
         Printf(false, "%FtTWO VECTORS");
 
@@ -296,7 +298,7 @@ void TextWindow::DescribeSelection(void) {
 
         if(fabs(theta) < 0.01) {
             double d = (p1.Minus(p0)).Dot(n0);
-            Printf(true,  "      distance = %Fi%s", SS.MmToString(d));
+            Printf(true,  "      distance = %Fi%s", SS.MmToString(d).c_str());
         }
     } else if(gs.n == 0 && gs.stylables > 0) {
         Printf(false, "%FtSELECTED:%E comment text");
@@ -311,7 +313,7 @@ void TextWindow::DescribeSelection(void) {
                    c->other ? CHECK_TRUE : CHECK_FALSE);
         } else {
             Printf(false, "%FtSELECTED:%E %s",
-                c->DescriptionString());
+            c->DescriptionString().c_str());
         }
     } else {
         int n = SS.GW.selection.n;
@@ -327,7 +329,7 @@ void TextWindow::DescribeSelection(void) {
         Printf(true, "%Fl%D%f%Ll(assign to style %s)%E",
             shown.style.v,
             &ScreenAssignSelectionToStyle,
-            s->DescriptionString());
+            s->DescriptionString().c_str());
     }
     // If any of the selected entities have an assigned style, then offer
     // the option to remove that style.
diff --git a/src/drawconstraint.cpp b/src/drawconstraint.cpp
index 82a1708b..f9b8f9b0 100644
--- a/src/drawconstraint.cpp
+++ b/src/drawconstraint.cpp
@@ -57,31 +57,31 @@ double Constraint::EllipticalInterpolation(double rx, double ry, double theta) {
     return v;
 }
 
-char *Constraint::Label(void) {
-    static char Ret[1024];
+std::string Constraint::Label(void) {
+    std::string result;
     if(type == ANGLE) {
-        sprintf(Ret, "%.2f", valA);
+        result = ssprintf("%.2f", valA);
     } else if(type == LENGTH_RATIO) {
-        sprintf(Ret, "%.3f:1", valA);
+        result = ssprintf("%.3f:1", valA);
     } else if(type == LENGTH_DIFFERENCE) {
-        sprintf(Ret, "%.3f", valA);
+        result = ssprintf("%.3f", valA);
     } else if(type == COMMENT) {
-        strcpy(Ret, comment.str);
+        result = comment;
     } else if(type == DIAMETER) {
         if(!other) {
             // leading spaces for diameter symbol
-            sprintf(Ret, "  %s", SS.MmToString(valA));
+            result = "  " + SS.MmToString(valA);
         } else {
-            sprintf(Ret, "R%s", SS.MmToString(valA / 2));
+            result = "R" + SS.MmToString(valA / 2);
         }
     } else {
         // valA has units of distance
-        strcpy(Ret, SS.MmToString(fabs(valA)));
+        result = SS.MmToString(fabs(valA));
     }
     if(reference) {
-        strcat(Ret, " REF");
+        result += " REF";
     }
-    return Ret;
+    return result;
 }
 
 void Constraint::DoLabel(Vector ref, Vector *labelPos, Vector gr, Vector gu) {
@@ -92,8 +92,8 @@ void Constraint::DoLabel(Vector ref, Vector *labelPos, Vector gr, Vector gu) {
         th = DEFAULT_TEXT_HEIGHT;
     }
 
-    char *s = Label();
-    double swidth  = ssglStrWidth(s, th),
+    std::string s = Label();
+    double swidth  = ssglStrWidth(s.c_str(), th),
            sheight = ssglStrHeight(th);
 
     // By default, the reference is from the center; but the style could
@@ -124,7 +124,7 @@ void Constraint::DoLabel(Vector ref, Vector *labelPos, Vector gr, Vector gu) {
 
 
     if(dogd.drawing) {
-        ssglWriteTextRefCenter(s, th, ref, gr, gu, LineCallback, this);
+        ssglWriteTextRefCenter(s.c_str(), th, ref, gr, gu, LineCallback, this);
     } else {
         double l = swidth/2 - sheight/2;
         l = max(l, 5/SS.GW.scale);
@@ -163,9 +163,9 @@ int Constraint::DoLineTrimmedAgainstBox(Vector ref, Vector a, Vector b) {
            gr = SS.GW.projRight.WithMagnitude(1);
 
     double pixels = 1.0 / SS.GW.scale;
-    char *s = Label();
-    double swidth  = ssglStrWidth(s, DEFAULT_TEXT_HEIGHT) + 4*pixels,
-           sheight = ssglStrHeight(DEFAULT_TEXT_HEIGHT)   + 8*pixels;
+    std::string s = Label();
+    double swidth  = ssglStrWidth(s.c_str(), DEFAULT_TEXT_HEIGHT) + 4*pixels,
+           sheight = ssglStrHeight(DEFAULT_TEXT_HEIGHT) + 8*pixels;
 
     struct {
         Vector n;
@@ -370,7 +370,7 @@ void Constraint::DoArcForAngle(Vector a0, Vector da, Vector b0, Vector db,
         // complex and this looks pretty good.
         double tl = atan2(rm.Dot(gu), rm.Dot(gr));
         double adj = EllipticalInterpolation(
-            ssglStrWidth(Label(), DEFAULT_TEXT_HEIGHT)/2,
+            ssglStrWidth(Label().c_str(), DEFAULT_TEXT_HEIGHT)/2,
             ssglStrHeight(DEFAULT_TEXT_HEIGHT)/2,
             tl);
         *ref = (*ref).Plus(rm.WithMagnitude(adj + 3/SS.GW.scale));
diff --git a/src/drawentity.cpp b/src/drawentity.cpp
index b90436c1..743ce516 100644
--- a/src/drawentity.cpp
+++ b/src/drawentity.cpp
@@ -7,7 +7,7 @@
 //-----------------------------------------------------------------------------
 #include "solvespace.h"
 
-char *Entity::DescriptionString(void) {
+std::string Entity::DescriptionString(void) {
     if(h.isFromRequest()) {
         Request *r = SK.GetRequest(h.request());
         return r->DescriptionString();
@@ -446,7 +446,7 @@ void Entity::GenerateBezierCurves(SBezierList *sbl) {
             Vector v = topLeft.Minus(botLeft);
             Vector u = (v.Cross(n)).WithMagnitude(v.Magnitude());
 
-            SS.fonts.PlotString(font.str, str.str, 0, sbl, botLeft, u, v);
+            SS.fonts.PlotString(font.c_str(), str.c_str(), 0, sbl, botLeft, u, v);
             break;
         }
 
@@ -608,12 +608,12 @@ void Entity::DrawOrGetDistance(void) {
             if(dogd.drawing)
                 glDisable(GL_LINE_STIPPLE);
 
-            char *str = DescriptionString()+5;
+            std::string str = DescriptionString().substr(5);
             double th = DEFAULT_TEXT_HEIGHT;
             if(dogd.drawing) {
-                ssglWriteText(str, th, mm2, u, v, NULL, NULL);
+                ssglWriteText(str.c_str(), th, mm2, u, v, NULL, NULL);
             } else {
-                Vector pos = mm2.Plus(u.ScaledBy(ssglStrWidth(str, th)/2)).Plus(
+                Vector pos = mm2.Plus(u.ScaledBy(ssglStrWidth(str.c_str(), th)/2)).Plus(
                                       v.ScaledBy(ssglStrHeight(th)/2));
                 Point2d pp = SS.GW.ProjectPoint(pos);
                 dogd.dmin = min(dogd.dmin, pp.DistanceTo(dogd.mp) - 10);
diff --git a/src/dsc.h b/src/dsc.h
index e5e21fc2..61b3782c 100644
--- a/src/dsc.h
+++ b/src/dsc.h
@@ -397,16 +397,6 @@ public:
 
 };
 
-class NameStr {
-public:
-    char str[64];
-
-    inline void strcpy(const char *in) {
-        memcpy(str, in, min(strlen(in)+1, sizeof(str)));
-        str[sizeof(str)-1] = '\0';
-    }
-};
-
 class BandedMatrix {
 public:
     enum {
diff --git a/src/exportvector.cpp b/src/exportvector.cpp
index 1d11f8e7..e78b0e4c 100644
--- a/src/exportvector.cpp
+++ b/src/exportvector.cpp
@@ -661,19 +661,19 @@ void GCodeFileWriter::FinishAndCloseFile(void) {
 
             SPoint *pt = sc->l.First();
             fprintf(f, "G00 X%s Y%s\r\n",
-                    SS.MmToString(pt->p.x), SS.MmToString(pt->p.y));
+                    SS.MmToString(pt->p.x).c_str(), SS.MmToString(pt->p.y).c_str());
             fprintf(f, "G01 Z%s F%s\r\n",
-                SS.MmToString(depth), SS.MmToString(SS.gCode.plungeFeed));
+                    SS.MmToString(depth).c_str(), SS.MmToString(SS.gCode.plungeFeed).c_str());
 
             pt = sc->l.NextAfter(pt);
             for(; pt; pt = sc->l.NextAfter(pt)) {
                 fprintf(f, "G01 X%s Y%s F%s\r\n",
-                        SS.MmToString(pt->p.x), SS.MmToString(pt->p.y),
-                        SS.MmToString(SS.gCode.feed));
+                        SS.MmToString(pt->p.x).c_str(), SS.MmToString(pt->p.y).c_str(),
+                        SS.MmToString(SS.gCode.feed).c_str());
             }
             // Move up to a clearance plane 5mm above the work.
             fprintf(f, "G00 Z%s\r\n",
-                SS.MmToString(SS.gCode.depth < 0 ? +5 : -5));
+                    SS.MmToString(SS.gCode.depth < 0 ? +5 : -5).c_str());
         }
     }
 
diff --git a/src/expr.cpp b/src/expr.cpp
index 2f6a08ed..81702417 100644
--- a/src/expr.cpp
+++ b/src/expr.cpp
@@ -547,47 +547,31 @@ hParam Expr::ReferencedParams(ParamList *pl) {
 // Routines to pretty-print an expression. Mostly for debugging.
 //-----------------------------------------------------------------------------
 
-static char StringBuffer[4096];
-void Expr::App(const char *s, ...) {
-    va_list f;
-    va_start(f, s);
-    vsprintf(StringBuffer+strlen(StringBuffer), s, f);
-}
-const char *Expr::Print(void) {
+std::string Expr::Print(void) {
     if(!this) return "0";
 
-    StringBuffer[0] = '\0';
-    PrintW();
-    return StringBuffer;
-}
-
-void Expr::PrintW(void) {
     char c;
     switch(op) {
-        case PARAM:     App("param(%08x)", x.parh.v); break;
-        case PARAM_PTR: App("param(p%08x)", x.parp->h.v); break;
+        case PARAM:     return ssprintf("param(%08x)", x.parh.v);
+        case PARAM_PTR: return ssprintf("param(p%08x)", x.parp->h.v);
 
-        case CONSTANT:  App("%.3f", x.v); break;
+        case CONSTANT:  return ssprintf("%.3f", x.v);
 
         case PLUS:      c = '+'; goto p;
         case MINUS:     c = '-'; goto p;
         case TIMES:     c = '*'; goto p;
         case DIV:       c = '/'; goto p;
 p:
-            App("(");
-            a->PrintW();
-            App(" %c ", c);
-            b->PrintW();
-            App(")");
+            return "(" + a->Print() + " " + c + " " + b->Print() + ")";
             break;
 
-        case NEGATE:    App("(- "); a->PrintW(); App(")"); break;
-        case SQRT:      App("(sqrt "); a->PrintW(); App(")"); break;
-        case SQUARE:    App("(square "); a->PrintW(); App(")"); break;
-        case SIN:       App("(sin "); a->PrintW(); App(")"); break;
-        case COS:       App("(cos "); a->PrintW(); App(")"); break;
-        case ASIN:      App("(asin "); a->PrintW(); App(")"); break;
-        case ACOS:      App("(acos "); a->PrintW(); App(")"); break;
+        case NEGATE:    return "(- " + a->Print() + ")";
+        case SQRT:      return "(sqrt " + a->Print() + ")";
+        case SQUARE:    return "(square " + a->Print() + ")";
+        case SIN:       return "(sin " + a->Print() + ")";
+        case COS:       return "(cos " + a->Print() + ")";
+        case ASIN:      return "(asin " + a->Print() + ")";
+        case ACOS:      return "(acos " + a->Print() + ")";
 
         default: oops();
     }
diff --git a/src/expr.h b/src/expr.h
index d53b0b28..2bc97dae 100644
--- a/src/expr.h
+++ b/src/expr.h
@@ -65,7 +65,7 @@ public:
 
     Expr() { }
     Expr(double v) : op(CONSTANT) { x.v = v; }
-    
+
     static inline Expr *AllocExpr(void)
         { return (Expr *)AllocTemporary(sizeof(Expr)); }
 
@@ -99,9 +99,7 @@ public:
 
     void ParamsToPointers(void);
 
-    void App(const char *str, ...);
-    const char *Print(void);
-    void PrintW(void); // worker
+    std::string Print(void);
 
     // number of child nodes: 0 (e.g. constant), 1 (sqrt), or 2 (+)
     int Children(void);
diff --git a/src/file.cpp b/src/file.cpp
index d5d2ca7b..cf72bcf4 100644
--- a/src/file.cpp
+++ b/src/file.cpp
@@ -44,7 +44,7 @@ hGroup SolveSpaceUI::CreateDefaultDrawingGroup(void) {
     g.predef.q = Quaternion::From(1, 0, 0, 0);
     hRequest hr = Request::HREQUEST_REFERENCE_XY;
     g.predef.origin = hr.entity(1);
-    g.name.strcpy("sketch-in-plane");
+    g.name = "sketch-in-plane";
     SK.group.AddAndAssignId(&g);
     SK.GetGroup(g.h)->activeWorkplane = g.h.entity(0);
     return g.h;
@@ -56,7 +56,7 @@ void SolveSpaceUI::NewFile(void) {
     // Our initial group, that contains the references.
     Group g = {};
     g.visible = true;
-    g.name.strcpy("#references");
+    g.name = "#references";
     g.type = Group::DRAWING_3D;
     g.h = Group::HGROUP_REFERENCES;
     SK.group.Add(&g);
@@ -84,7 +84,7 @@ const SolveSpaceUI::SaveTable SolveSpaceUI::SAVED[] = {
     { 'g',  "Group.h.v",                'x',    &(SS.sv.g.h.v)                },
     { 'g',  "Group.type",               'd',    &(SS.sv.g.type)               },
     { 'g',  "Group.order",              'd',    &(SS.sv.g.order)              },
-    { 'g',  "Group.name",               'N',    &(SS.sv.g.name)               },
+    { 'g',  "Group.name",               'S',    &(SS.sv.g.name)               },
     { 'g',  "Group.activeWorkplane.v",  'x',    &(SS.sv.g.activeWorkplane.v)  },
     { 'g',  "Group.opA.v",              'x',    &(SS.sv.g.opA.v)              },
     { 'g',  "Group.opB.v",              'x',    &(SS.sv.g.opB.v)              },
@@ -112,8 +112,8 @@ const SolveSpaceUI::SaveTable SolveSpaceUI::SAVED[] = {
     { 'g',  "Group.allDimsReference",   'b',    &(SS.sv.g.allDimsReference)   },
     { 'g',  "Group.scale",              'f',    &(SS.sv.g.scale)              },
     { 'g',  "Group.remap",              'M',    &(SS.sv.g.remap)              },
-    { 'g',  "Group.impFile",            'P',    &(SS.sv.g.impFile)            },
-    { 'g',  "Group.impFileRel",         'P',    &(SS.sv.g.impFileRel)         },
+    { 'g',  "Group.impFile",            'S',    &(SS.sv.g.impFile)            },
+    { 'g',  "Group.impFileRel",         'S',    &(SS.sv.g.impFileRel)         },
 
     { 'p',  "Param.h.v.",               'x',    &(SS.sv.p.h.v)                },
     { 'p',  "Param.val",                'f',    &(SS.sv.p.val)                },
@@ -125,15 +125,15 @@ const SolveSpaceUI::SaveTable SolveSpaceUI::SAVED[] = {
     { 'r',  "Request.group.v",          'x',    &(SS.sv.r.group.v)            },
     { 'r',  "Request.construction",     'b',    &(SS.sv.r.construction)       },
     { 'r',  "Request.style",            'x',    &(SS.sv.r.style)              },
-    { 'r',  "Request.str",              'N',    &(SS.sv.r.str)                },
-    { 'r',  "Request.font",             'N',    &(SS.sv.r.font)               },
+    { 'r',  "Request.str",              'S',    &(SS.sv.r.str)                },
+    { 'r',  "Request.font",             'S',    &(SS.sv.r.font)               },
 
     { 'e',  "Entity.h.v",               'x',    &(SS.sv.e.h.v)                },
     { 'e',  "Entity.type",              'd',    &(SS.sv.e.type)               },
     { 'e',  "Entity.construction",      'b',    &(SS.sv.e.construction)       },
     { 'e',  "Entity.style",             'x',    &(SS.sv.e.style)              },
-    { 'e',  "Entity.str",               'N',    &(SS.sv.e.str)                },
-    { 'e',  "Entity.font",              'N',    &(SS.sv.e.font)               },
+    { 'e',  "Entity.str",               'S',    &(SS.sv.e.str)                },
+    { 'e',  "Entity.font",              'S',    &(SS.sv.e.font)               },
     { 'e',  "Entity.point[0].v",        'x',    &(SS.sv.e.point[0].v)         },
     { 'e',  "Entity.point[1].v",        'x',    &(SS.sv.e.point[1].v)         },
     { 'e',  "Entity.point[2].v",        'x',    &(SS.sv.e.point[2].v)         },
@@ -175,14 +175,14 @@ const SolveSpaceUI::SaveTable SolveSpaceUI::SAVED[] = {
     { 'c',  "Constraint.other",         'b',    &(SS.sv.c.other)              },
     { 'c',  "Constraint.other2",        'b',    &(SS.sv.c.other2)             },
     { 'c',  "Constraint.reference",     'b',    &(SS.sv.c.reference)          },
-    { 'c',  "Constraint.comment",       'N',    &(SS.sv.c.comment)            },
+    { 'c',  "Constraint.comment",       'S',    &(SS.sv.c.comment)            },
     { 'c',  "Constraint.disp.offset.x", 'f',    &(SS.sv.c.disp.offset.x)      },
     { 'c',  "Constraint.disp.offset.y", 'f',    &(SS.sv.c.disp.offset.y)      },
     { 'c',  "Constraint.disp.offset.z", 'f',    &(SS.sv.c.disp.offset.z)      },
     { 'c',  "Constraint.disp.style",    'x',    &(SS.sv.c.disp.style)         },
 
     { 's',  "Style.h.v",                'x',    &(SS.sv.s.h.v)                },
-    { 's',  "Style.name",               'N',    &(SS.sv.s.name)               },
+    { 's',  "Style.name",               'S',    &(SS.sv.s.name)               },
     { 's',  "Style.width",              'f',    &(SS.sv.s.width)              },
     { 's',  "Style.widthAs",            'd',    &(SS.sv.s.widthAs)            },
     { 's',  "Style.textHeight",         'f',    &(SS.sv.s.textHeight)         },
@@ -200,8 +200,7 @@ const SolveSpaceUI::SaveTable SolveSpaceUI::SAVED[] = {
 
 union SAVEDptr {
     IdList<EntityMap,EntityId> M;
-    NameStr   N;
-    /* std::string P */
+    /* std::string S; */
     bool      b;
     RgbaColor c;
     int       d;
@@ -217,15 +216,14 @@ void SolveSpaceUI::SaveUsingTable(int type) {
         int fmt = SAVED[i].fmt;
         union SAVEDptr *p = (union SAVEDptr *)SAVED[i].ptr;
         // Any items that aren't specified are assumed to be zero
-        if(fmt == 'N' && p->N.str[0] == '\0')   continue;
+        if(fmt == 'S' && ((std::string*)p)->empty()) continue;
         if(fmt == 'd' && p->d == 0)             continue;
         if(fmt == 'f' && EXACT(p->f == 0.0))    continue;
         if(fmt == 'x' && p->x == 0)             continue;
 
         fprintf(fh, "%s=", SAVED[i].desc);
         switch(fmt) {
-            case 'N': fprintf(fh, "%s",    p->N.str);           break;
-            case 'P': fprintf(fh, "%s",    ((std::string*)p)->c_str()); break;
+            case 'S': fprintf(fh, "%s",    ((std::string*)p)->c_str()); break;
             case 'b': fprintf(fh, "%d",    p->b ? 1 : 0);       break;
             case 'c': fprintf(fh, "%08x",  p->c.ToPackedInt()); break;
             case 'd': fprintf(fh, "%d",    p->d);               break;
@@ -373,7 +371,7 @@ void SolveSpaceUI::LoadUsingTable(char *key, char *val) {
             union SAVEDptr *p = (union SAVEDptr *)SAVED[i].ptr;
             unsigned int u = 0;
             switch(SAVED[i].fmt) {
-                case 'N': p->N.strcpy(val);        break;
+                case 'S': (*(std::string*)p) = val; break;
                 case 'b': p->b = (atoi(val) != 0); break;
                 case 'd': p->d = atoi(val);        break;
                 case 'f': p->f = atof(val);        break;
diff --git a/src/group.cpp b/src/group.cpp
index 68420571..6333696b 100644
--- a/src/group.cpp
+++ b/src/group.cpp
@@ -66,12 +66,12 @@ void Group::MenuGroup(int id) {
     switch(id) {
         case GraphicsWindow::MNU_GROUP_3D:
             g.type = DRAWING_3D;
-            g.name.strcpy("sketch-in-3d");
+            g.name = "sketch-in-3d";
             break;
 
         case GraphicsWindow::MNU_GROUP_WRKPL:
             g.type = DRAWING_WORKPLANE;
-            g.name.strcpy("sketch-in-plane");
+            g.name = "sketch-in-plane";
             if(gs.points == 1 && gs.n == 1) {
                 g.subtype = WORKPLANE_BY_POINT_ORTHO;
 
@@ -122,7 +122,7 @@ void Group::MenuGroup(int id) {
             g.opA = SS.GW.activeGroup;
             g.predef.entityB = SS.GW.ActiveWorkplane();
             g.subtype = ONE_SIDED;
-            g.name.strcpy("extrude");
+            g.name = "extrude";
             break;
 
         case GraphicsWindow::MNU_GROUP_LATHE:
@@ -144,7 +144,7 @@ void Group::MenuGroup(int id) {
             }
             g.type = LATHE;
             g.opA = SS.GW.activeGroup;
-            g.name.strcpy("lathe");
+            g.name = "lathe";
             break;
 
         case GraphicsWindow::MNU_GROUP_ROT: {
@@ -170,7 +170,7 @@ void Group::MenuGroup(int id) {
             g.opA = SS.GW.activeGroup;
             g.valA = 3;
             g.subtype = ONE_SIDED;
-            g.name.strcpy("rotate");
+            g.name = "rotate";
             break;
         }
 
@@ -181,7 +181,7 @@ void Group::MenuGroup(int id) {
             g.subtype = ONE_SIDED;
             g.predef.entityB = SS.GW.ActiveWorkplane();
             g.activeWorkplane = SS.GW.ActiveWorkplane();
-            g.name.strcpy("translate");
+            g.name = "translate";
             break;
 
         case GraphicsWindow::MNU_GROUP_IMPORT: {
@@ -212,9 +212,9 @@ void Group::MenuGroup(int id) {
             }
 
             if(groupName.length() > 0) {
-                g.name.strcpy(groupName.substr(0, 64).c_str());
+                g.name = groupName;
             } else {
-                g.name.strcpy("import");
+                g.name = "import";
             }
 
             g.meshCombine = COMBINE_AS_ASSEMBLE;
@@ -274,14 +274,12 @@ void Group::TransformImportedBy(Vector t, Quaternion q) {
     SK.GetParam(qz)->val = qg.vz;
 }
 
-char *Group::DescriptionString(void) {
-    static char ret[100];
-    if(name.str[0]) {
-        sprintf(ret, "g%03x-%s", h.v, name.str);
+std::string Group::DescriptionString(void) {
+    if(name.empty()) {
+        return ssprintf("g%03x-(unnamed)", h.v);
     } else {
-        sprintf(ret, "g%03x-(unnamed)", h.v);
+        return ssprintf("g%03x-%s", h.v, name.c_str());
     }
-    return ret;
 }
 
 void Group::Activate(void) {
@@ -636,8 +634,8 @@ void Group::CopyEntity(IdList<Entity,hEntity> *el,
     en.group = h;
     en.construction = ep->construction;
     en.style = ep->style;
-    en.str.strcpy(ep->str.str);
-    en.font.strcpy(ep->font.str);
+    en.str = ep->str;
+    en.font = ep->font;
 
     switch(ep->type) {
         case Entity::WORKPLANE:
diff --git a/src/gtk/gtkmain.cpp b/src/gtk/gtkmain.cpp
index 56d40a78..f119ec71 100644
--- a/src/gtk/gtkmain.cpp
+++ b/src/gtk/gtkmain.cpp
@@ -387,7 +387,7 @@ public:
             connect(sigc::mem_fun(this, &EditorOverlay::on_activate));
     }
 
-    void start_editing(int x, int y, const char *val) {
+    void start_editing(int x, int y, const std::string &val) {
         move(_entry, x, y - 4);
         _entry.set_text(val);
         if(!_entry.is_visible()) {
@@ -720,7 +720,7 @@ bool FullScreenIsActive(void) {
     return GW->is_fullscreen();
 }
 
-void ShowGraphicsEditControl(int x, int y, char *val) {
+void ShowGraphicsEditControl(int x, int y, const std::string &val) {
     Gdk::Rectangle rect = GW->get_widget().get_allocation();
 
     // Convert to ij (vs. xy) style coordinates,
@@ -1378,7 +1378,7 @@ void SetMousePointerToHand(bool is_hand) {
     TW->get_widget().set_cursor_hand(is_hand);
 }
 
-void ShowTextEditControl(int x, int y, char *val) {
+void ShowTextEditControl(int x, int y, const std::string &val) {
     TW->get_overlay().start_editing(x, y, val);
 }
 
diff --git a/src/mouse.cpp b/src/mouse.cpp
index e9faf516..240caf1b 100644
--- a/src/mouse.cpp
+++ b/src/mouse.cpp
@@ -476,7 +476,7 @@ void GraphicsWindow::ContextMenuListStyles(void) {
     for(s = SK.style.First(); s; s = SK.style.NextAfter(s)) {
         if(s->h.v < Style::FIRST_CUSTOM) continue;
 
-        AddContextMenuItem(s->DescriptionString(), CMNU_FIRST_STYLE + s->h.v);
+        AddContextMenuItem(s->DescriptionString().c_str(), CMNU_FIRST_STYLE + s->h.v);
         empty = false;
     }
 
@@ -933,8 +933,8 @@ void GraphicsWindow::MouseLeftDown(double mx, double my) {
             }
             hr = AddRequest(Request::TTF_TEXT);
             Request *r = SK.GetRequest(hr);
-            r->str.strcpy("Abc");
-            r->font.strcpy("arial.ttf");
+            r->str = "Abc";
+            r->font = "arial.ttf";
 
             SK.GetEntity(hr.entity(1))->PointForceTo(v);
             SK.GetEntity(hr.entity(2))->PointForceTo(v);
@@ -952,7 +952,7 @@ void GraphicsWindow::MouseLeftDown(double mx, double my) {
             c.workplane   = SS.GW.ActiveWorkplane();
             c.type        = Constraint::COMMENT;
             c.disp.offset = v;
-            c.comment.strcpy("NEW COMMENT -- DOUBLE-CLICK TO EDIT");
+            c.comment = "NEW COMMENT -- DOUBLE-CLICK TO EDIT";
             Constraint::AddConstraint(&c);
             break;
         }
@@ -1145,16 +1145,16 @@ void GraphicsWindow::MouseLeftDoubleClick(double mx, double my) {
         Vector p3 = c->GetLabelPos();
         Point2d p2 = ProjectPoint(p3);
 
-        char s[1024];
+        std::string edit_value;
         switch(c->type) {
             case Constraint::COMMENT:
-                strcpy(s, c->comment.str);
+                edit_value = c->comment;
                 break;
 
             case Constraint::ANGLE:
             case Constraint::LENGTH_RATIO:
             case Constraint::LENGTH_DIFFERENCE:
-                sprintf(s, "%.3f", c->valA);
+                edit_value = ssprintf("%.3f", c->valA);
                 break;
 
             default: {
@@ -1164,26 +1164,26 @@ void GraphicsWindow::MouseLeftDoubleClick(double mx, double my) {
                 if(c->type == Constraint::DIAMETER && c->other)
                     v /= 2;
 
-                char *def = SS.MmToString(v);
+                std::string def = SS.MmToString(v);
                 double eps = 1e-12;
                 if(fabs(SS.StringToMm(def) - v) < eps) {
                     // Show value with default number of digits after decimal,
                     // which is at least enough to represent it exactly.
-                    strcpy(s, def);
+                    edit_value = def;
                 } else {
                     // Show value with as many digits after decimal as
                     // required to represent it exactly, up to 10.
                     v /= SS.MmPerUnit();
                     int i;
                     for(i = 0; i <= 10; i++) {
-                        sprintf(s, "%.*f", i, v);
-                        if(fabs(atof(s) - v) < eps) break;
+                        edit_value = ssprintf("%.*f", i, v);
+                        if(fabs(std::stod(edit_value) - v) < eps) break;
                     }
                 }
                 break;
             }
         }
-        ShowGraphicsEditControl((int)p2.x, (int)p2.y-4, s);
+        ShowGraphicsEditControl((int)p2.x, (int)p2.y-4, edit_value);
     }
 }
 
@@ -1193,7 +1193,7 @@ void GraphicsWindow::EditControlDone(const char *s) {
 
     if(c->type == Constraint::COMMENT) {
         SS.UndoRemember();
-        c->comment.strcpy(s);
+        c->comment = s;
         return;
     }
 
diff --git a/src/request.cpp b/src/request.cpp
index 15297ca3..2da6eafb 100644
--- a/src/request.cpp
+++ b/src/request.cpp
@@ -102,8 +102,8 @@ void Request::Generate(IdList<Entity,hEntity> *entity,
     e.style = style;
     e.workplane = workplane;
     e.construction = construction;
-    e.str.strcpy(str.str);
-    e.font.strcpy(font.str);
+    e.str = str;
+    e.font = font;
     e.h = h.entity(0);
 
     // And generate entities for the points
@@ -169,7 +169,7 @@ void Request::Generate(IdList<Entity,hEntity> *entity,
     if(et) entity->Add(&e);
 }
 
-char *Request::DescriptionString(void) {
+std::string Request::DescriptionString(void) {
     const char *s;
     if(h.v == Request::HREQUEST_REFERENCE_XY.v) {
         s = "#XY";
@@ -180,9 +180,8 @@ char *Request::DescriptionString(void) {
     } else {
         s = EntReqTable::DescriptionForRequest(type);
     }
-    static char ret[100];
-    sprintf(ret, "r%03x-%s", h.v, s);
-    return ret;
+
+    return ssprintf("r%03x-%s", h.v, s);
 }
 
 hParam Request::AddParam(IdList<Param,hParam> *param, hParam hp) {
diff --git a/src/sketch.h b/src/sketch.h
index c61bdbf0..b86200b2 100644
--- a/src/sketch.h
+++ b/src/sketch.h
@@ -195,11 +195,11 @@ public:
     SShell      impShell;
     EntityList  impEntity;
 
-    NameStr     name;
+    std::string     name;
 
 
     void Activate(void);
-    char *DescriptionString(void);
+    std::string DescriptionString(void);
     void Clear(void);
 
     static void AddParam(ParamList *param, hParam hp, double v);
@@ -284,13 +284,13 @@ public:
     hStyle      style;
 
     bool        construction;
-    NameStr     str;
-    NameStr     font;
+    std::string str;
+    std::string font;
 
     static hParam AddParam(ParamList *param, hParam hp);
     void Generate(EntityList *entity, ParamList *param);
 
-    char *DescriptionString(void);
+    std::string DescriptionString(void);
 
     void Clear(void) {}
 };
@@ -357,8 +357,8 @@ public:
     Quaternion  numNormal;
     double      numDistance;
 
-    NameStr     str;
-    NameStr     font;
+    std::string str;
+    std::string font;
 
     // For entities that are derived by a transformation, the number of
     // times to apply the transformation.
@@ -491,7 +491,7 @@ public:
 
     void CalculateNumerical(bool forExport);
 
-    char *DescriptionString(void);
+    std::string DescriptionString(void);
 };
 
 class EntReqTable {
@@ -606,7 +606,7 @@ public:
     bool        other2;
 
     bool        reference;  // a ref dimension, that generates no eqs
-    NameStr     comment;    // since comments are represented as constraints
+    std::string comment;    // since comments are represented as constraints
 
     bool HasLabel(void);
 
@@ -654,7 +654,7 @@ public:
     void LineDrawOrGetDistance(Vector a, Vector b);
     void DrawOrGetDistance(Vector *labelPos);
     double EllipticalInterpolation(double rx, double ry, double theta);
-    char *Label(void);
+    std::string Label(void);
     void DoArcForAngle(Vector a0, Vector da, Vector b0, Vector db,
                         Vector offset, Vector *ref);
     void DoLineWithArrows(Vector ref, Vector a, Vector b, bool onlyOneExt);
@@ -665,7 +665,7 @@ public:
     void DoEqualLenTicks(Vector a, Vector b, Vector gn);
     void DoEqualRadiusTicks(hEntity he);
 
-    char *DescriptionString(void);
+    std::string DescriptionString(void);
 
     static void AddConstraint(Constraint *c, bool rememberForUndo);
     static void AddConstraint(Constraint *c);
@@ -726,7 +726,7 @@ public:
         FIRST_CUSTOM   = 0x100
     };
 
-    NameStr     name;
+    std::string name;
 
     enum {
         UNITS_AS_PIXELS   = 0,
@@ -760,9 +760,9 @@ public:
     } Default;
     static const Default Defaults[];
 
-    static char *CnfColor(const char *prefix);
-    static char *CnfWidth(const char *prefix);
-    static char *CnfPrefixToName(const char *prefix);
+    static std::string CnfColor(const std::string &prefix);
+    static std::string CnfWidth(const std::string &prefix);
+    static std::string CnfPrefixToName(const std::string &prefix);
 
     static void CreateAllDefaultStyles(void);
     static void CreateDefaultStyle(hStyle h);
@@ -785,7 +785,7 @@ public:
     static bool Exportable(int hs);
     static hStyle ForEntity(hEntity he);
 
-    char *DescriptionString(void);
+    std::string DescriptionString(void);
 
     void Clear(void) {}
 };
@@ -836,8 +836,8 @@ public:
     int         type;
     int         extraPoints;
     hStyle      style;
-    NameStr     str;
-    NameStr     font;
+    std::string str;
+    std::string font;
     bool        construction;
 
     Vector      point[MAX_POINTS_IN_ENTITY];
diff --git a/src/solvespace.cpp b/src/solvespace.cpp
index 90f889ae..56597b1b 100644
--- a/src/solvespace.cpp
+++ b/src/solvespace.cpp
@@ -242,26 +242,18 @@ const char *SolveSpaceUI::UnitName(void) {
         return "mm";
     }
 }
-char *SolveSpaceUI::MmToString(double v) {
-    static int WhichBuf;
-    static char Bufs[8][128];
-
-    WhichBuf++;
-    if(WhichBuf >= 8 || WhichBuf < 0) WhichBuf = 0;
-
-    char *s = Bufs[WhichBuf];
+std::string SolveSpaceUI::MmToString(double v) {
     if(viewUnits == UNIT_INCHES) {
-        sprintf(s, "%.*f", afterDecimalInch, v/25.4);
+        return ssprintf("%.*f", afterDecimalInch, v/25.4);
     } else {
-        sprintf(s, "%.*f", afterDecimalMm, v);
+        return ssprintf("%.*f", afterDecimalMm, v);
     }
-    return s;
 }
 double SolveSpaceUI::ExprToMm(Expr *e) {
     return (e->Eval()) * MmPerUnit();
 }
-double SolveSpaceUI::StringToMm(const char *str) {
-    return atof(str) * MmPerUnit();
+double SolveSpaceUI::StringToMm(const std::string &str) {
+    return std::stod(str) * MmPerUnit();
 }
 double SolveSpaceUI::ChordTolMm(void) {
     return SS.chordTol / SS.GW.scale;
diff --git a/src/solvespace.h b/src/solvespace.h
index 3dcd3b58..03d21de8 100644
--- a/src/solvespace.h
+++ b/src/solvespace.h
@@ -65,6 +65,11 @@ using std::min;
 using std::max;
 using std::swap;
 
+#if defined(__GNUC__)
+__attribute__((__format__ (__printf__, 1, 2)))
+#endif
+std::string ssprintf(const char *fmt, ...);
+
 inline int WRAP(int v, int n) {
     // Clamp it to the range [0, n)
     while(v >= n) v -= n;
@@ -220,10 +225,10 @@ void CheckMenuById(int id, bool checked);
 void RadioMenuById(int id, bool selected);
 void EnableMenuById(int id, bool enabled);
 
-void ShowGraphicsEditControl(int x, int y, char *s);
+void ShowGraphicsEditControl(int x, int y, const std::string &str);
 void HideGraphicsEditControl(void);
 bool GraphicsEditControlIsVisible(void);
-void ShowTextEditControl(int x, int y, char *s);
+void ShowTextEditControl(int x, int y, const std::string &str);
 void HideTextEditControl(void);
 bool TextEditControlIsVisible(void);
 void MoveTextScrollbarTo(int pos, int maxPos, int page);
@@ -462,7 +467,7 @@ public:
     } IntPoint;
 
     std::string fontFile;
-    NameStr     name;
+    std::string name;
     bool        loaded;
 
     // The font itself, plus the mapping from ASCII codes to glyphs
@@ -502,7 +507,7 @@ public:
     void Flush(void);
     void Handle(int *dx, int x, int y, bool onCurve);
     void PlotCharacter(int *dx, int c, double spacing);
-    void PlotString(char *str, double spacing,
+    void PlotString(const char *str, double spacing,
                     SBezierList *sbl, Vector origin, Vector u, Vector v);
 
     Vector TransformIntPoint(int x, int y);
@@ -517,7 +522,7 @@ public:
 
     void LoadAll(void);
 
-    void PlotString(const std::string &font, char *str, double spacing,
+    void PlotString(const std::string &font, const char *str, double spacing,
                     SBezierList *sbl, Vector origin, Vector u, Vector v);
 };
 
@@ -785,9 +790,9 @@ public:
     int      afterDecimalInch;
     int      autosaveInterval; // in minutes
 
-    char *MmToString(double v);
+    std::string MmToString(double v);
     double ExprToMm(Expr *e);
-    double StringToMm(const char *s);
+    double StringToMm(const std::string &s);
     const char *UnitName(void);
     double MmPerUnit(void);
     int UnitDigitsAfterDecimal(void);
diff --git a/src/style.cpp b/src/style.cpp
index a6eaf013..d5130038 100644
--- a/src/style.cpp
+++ b/src/style.cpp
@@ -25,30 +25,22 @@ const Style::Default Style::Defaults[] = {
     { { 0 },            NULL,           RGBf(0.0, 0.0, 0.0), 0.0 }
 };
 
-char *Style::CnfColor(const char *prefix) {
-    static char name[100];
-    sprintf(name, "Style_%s_Color", prefix);
-    return name;
+std::string Style::CnfColor(const std::string &prefix) {
+    return "Style_" + prefix + "_Color";
 }
-char *Style::CnfWidth(const char *prefix) {
-    static char name[100];
-    sprintf(name, "Style_%s_Width", prefix);
-    return name;
+std::string Style::CnfWidth(const std::string &prefix) {
+    return "Style_" + prefix + "_Width";
 }
 
-char *Style::CnfPrefixToName(const char *prefix) {
-    static char name[100];
-    int i = 0, j;
-    strcpy(name, "#def-");
-    j = 5;
-    while(prefix[i] && j < 90) {
-        if(isupper(prefix[i]) && i != 0) {
-            name[j++] = '-';
-        }
-        name[j++] = (char)tolower(prefix[i]);
-        i++;
+std::string Style::CnfPrefixToName(const std::string &prefix) {
+    std::string name = "#def-";
+
+    for(int i = 0; i < prefix.length(); i++) {
+        if(isupper(prefix[i]) && i != 0)
+            name += '-';
+        name += tolower(prefix[i]);
     }
-    name[j++] = '\0';
+
     return name;
 }
 
@@ -86,9 +78,9 @@ void Style::CreateDefaultStyle(hStyle h) {
     ns.fillColor    = RGBf(0.3, 0.3, 0.3);
     ns.h            = h;
     if(isDefaultStyle) {
-        ns.name.strcpy(CnfPrefixToName(d->cnfPrefix));
+        ns.name = CnfPrefixToName(d->cnfPrefix);
     } else {
-        ns.name.strcpy("new-custom-style");
+        ns.name = "new-custom-style";
     }
 
     SK.style.Add(&ns);
@@ -110,7 +102,7 @@ void Style::LoadFactoryDefaults(void) {
         s->exportable   = true;
         s->filled       = false;
         s->fillColor    = RGBf(0.3, 0.3, 0.3);
-        s->name.strcpy(CnfPrefixToName(d->cnfPrefix));
+        s->name         = CnfPrefixToName(d->cnfPrefix);
     }
     SS.backgroundColor = RGBi(0, 0, 0);
     if(SS.bgImage.fromFile) MemFree(SS.bgImage.fromFile);
@@ -319,14 +311,12 @@ hStyle Style::ForEntity(hEntity he) {
     return hs;
 }
 
-char *Style::DescriptionString(void) {
-    static char ret[100];
-    if(name.str[0]) {
-        sprintf(ret, "s%03x-%s", h.v, name.str);
+std::string Style::DescriptionString(void) {
+    if(name.empty()) {
+        return ssprintf("s%03x-(unnamed)", h.v);
     } else {
-        sprintf(ret, "s%03x-(unnamed)", h.v);
+        return ssprintf("s%03x-%s", h.v, name.c_str());
     }
-    return ret;
 }
 
 
@@ -444,7 +434,7 @@ void TextWindow::ShowListOfStyles(void) {
             &s->color,
             darkbg ? 'd' : 'a',
             ScreenShowStyleInfo, s->h.v,
-            s->DescriptionString());
+            s->DescriptionString().c_str());
 
         darkbg = !darkbg;
     }
@@ -488,7 +478,7 @@ void TextWindow::ShowListOfStyles(void) {
 void TextWindow::ScreenChangeStyleName(int link, uint32_t v) {
     hStyle hs = { v };
     Style *s = Style::Get(hs);
-    SS.TW.ShowEditControl(10, 12, s->name.str);
+    SS.TW.ShowEditControl(10, 12, s->name.c_str());
     SS.TW.edit.style = hs;
     SS.TW.edit.meaning = EDIT_STYLE_NAME;
 }
@@ -512,11 +502,11 @@ void TextWindow::ScreenChangeStyleWidthOrTextHeight(int link, uint32_t v) {
     double val   = (link == 't') ? s->textHeight   : s->width;
     int    units = (link == 't') ? s->textHeightAs : s->widthAs;
 
-    char str[300];
+    std::string edit_value;
     if(units == Style::UNITS_AS_PIXELS) {
-        sprintf(str, "%.2f", val);
+        edit_value = ssprintf("%.2f", val);
     } else {
-        strcpy(str, SS.MmToString(val));
+        edit_value = SS.MmToString(val);
     }
     int row = 0, col = 9;
     if(link == 'w') {
@@ -527,7 +517,7 @@ void TextWindow::ScreenChangeStyleWidthOrTextHeight(int link, uint32_t v) {
         row = 33;               // text height (for custom styles only)
         col++;
     }
-    SS.TW.ShowEditControl(row, col, str);
+    SS.TW.ShowEditControl(row, col, edit_value);
     SS.TW.edit.style = hs;
     SS.TW.edit.meaning = (link == 't') ? EDIT_STYLE_TEXT_HEIGHT :
                                          EDIT_STYLE_WIDTH;
@@ -536,9 +526,7 @@ void TextWindow::ScreenChangeStyleWidthOrTextHeight(int link, uint32_t v) {
 void TextWindow::ScreenChangeStyleTextAngle(int link, uint32_t v) {
     hStyle hs = { v };
     Style *s = Style::Get(hs);
-    char str[300];
-    sprintf(str, "%.2f", s->textAngle);
-    SS.TW.ShowEditControl(37, 9, str);
+    SS.TW.ShowEditControl(37, 9, ssprintf("%.2f", s->textAngle));
     SS.TW.edit.style = hs;
     SS.TW.edit.meaning = EDIT_STYLE_TEXT_ANGLE;
 }
@@ -700,7 +688,7 @@ bool TextWindow::EditControlDoneForStyles(const char *str) {
             } else {
                 SS.UndoRemember();
                 s = Style::Get(edit.style);
-                s->name.strcpy(str);
+                s->name = str;
             }
             break;
 
@@ -727,11 +715,11 @@ void TextWindow::ShowStyleInfo(void) {
     Style *s = Style::Get(shown.style);
 
     if(s->h.v < Style::FIRST_CUSTOM) {
-        Printf(true, "%FtSTYLE  %E%s ", s->DescriptionString());
+        Printf(true, "%FtSTYLE  %E%s ", s->DescriptionString().c_str());
     } else {
         Printf(true, "%FtSTYLE  %E%s "
                      "[%Fl%Ll%D%frename%E/%Fl%Ll%D%fdel%E]",
-            s->DescriptionString(),
+            s->DescriptionString().c_str(),
             s->h.v, &ScreenChangeStyleName,
             s->h.v, &ScreenDeleteStyle);
     }
@@ -750,7 +738,7 @@ void TextWindow::ShowStyleInfo(void) {
             (s->h.v < Style::FIRST_CUSTOM) ? 'w' : 'W');
     } else {
         Printf(false, "   %Ftwidth%E %s %D%f%Lp%Fl[change]%E",
-            SS.MmToString(s->width),
+            SS.MmToString(s->width).c_str(),
             s->h.v, &ScreenChangeStyleWidthOrTextHeight,
             (s->h.v < Style::FIRST_CUSTOM) ? 'w' : 'W');
     }
@@ -797,7 +785,7 @@ void TextWindow::ShowStyleInfo(void) {
             chng);
     } else {
         Printf(false, "%Ba   %Ftheight %E%s %D%f%Lt%Fl%s%E",
-            SS.MmToString(s->textHeight),
+            SS.MmToString(s->textHeight).c_str(),
             s->h.v, &ScreenChangeStyleWidthOrTextHeight,
             chng);
     }
diff --git a/src/textscreens.cpp b/src/textscreens.cpp
index c8b320c4..fe46cacd 100644
--- a/src/textscreens.cpp
+++ b/src/textscreens.cpp
@@ -16,21 +16,22 @@ void TextWindow::ScreenHome(int link, uint32_t v) {
 void TextWindow::ShowHeader(bool withNav) {
     ClearScreen();
 
-    char cd[1024], cd2[1024];
+    const char *header;
+    std::string desc;
     if(SS.GW.LockedInWorkplane()) {
-        sprintf(cd, "in plane: ");
-        strcpy(cd2, SK.GetEntity(SS.GW.ActiveWorkplane())->DescriptionString());
+        header = "in plane: ";
+        desc = SK.GetEntity(SS.GW.ActiveWorkplane())->DescriptionString();
     } else {
-        sprintf(cd, "drawing / constraining in 3d");
-        strcpy(cd2, "");
+        header = "drawing / constraining in 3d";
+        desc = "";
     }
 
     // Navigation buttons
     if(withNav) {
         Printf(false, " %Fl%Lh%fhome%E   %Ft%s%E%s",
-            (&TextWindow::ScreenHome), cd, cd2);
+            (&TextWindow::ScreenHome), header, desc.c_str());
     } else {
-        Printf(false, "        %Ft%s%E%s", cd, cd2);
+        Printf(false, "        %Ft%s%E%s", header, desc.c_str());
     }
 
     // Leave space for the icons that are painted here.
@@ -108,7 +109,7 @@ void TextWindow::ShowListOfGroups(void) {
     bool afterActive = false;
     for(i = 0; i < SK.group.n; i++) {
         Group *g = &(SK.group.elem[i]);
-        char *s = g->DescriptionString();
+        std::string s = g->DescriptionString();
         bool active = (g->h.v == SS.GW.activeGroup.v);
         bool shown = g->visible;
         bool ok = (g->solved.how == System::SOLVED_OKAY);
@@ -133,7 +134,7 @@ void TextWindow::ShowListOfGroups(void) {
                 ok ? "ok" : "",
                 ok ? "" : "NO",
             // Link to a screen that gives more details on the group
-            g->h.v, (&TextWindow::ScreenSelectGroup), s);
+            g->h.v, (&TextWindow::ScreenSelectGroup), s.c_str());
 
         if(active) afterActive = true;
     }
@@ -246,16 +247,14 @@ void TextWindow::ScreenChangeExprA(int link, uint32_t v) {
 }
 void TextWindow::ScreenChangeGroupName(int link, uint32_t v) {
     Group *g = SK.GetGroup(SS.TW.shown.group);
-    SS.TW.ShowEditControl(7, 12, g->DescriptionString()+5);
+    SS.TW.ShowEditControl(7, 12, g->DescriptionString().substr(5));
     SS.TW.edit.meaning = EDIT_GROUP_NAME;
     SS.TW.edit.group.v = v;
 }
 void TextWindow::ScreenChangeGroupScale(int link, uint32_t v) {
     Group *g = SK.GetGroup(SS.TW.shown.group);
 
-    char str[1024];
-    sprintf(str, "%.3f", g->scale);
-    SS.TW.ShowEditControl(14, 13, str);
+    SS.TW.ShowEditControl(14, 13, ssprintf("%.3f", g->scale));
     SS.TW.edit.meaning = EDIT_GROUP_SCALE;
     SS.TW.edit.group.v = v;
 }
@@ -279,11 +278,11 @@ void TextWindow::ShowGroupInfo(void) {
     const char *s = "???";
 
     if(shown.group.v == Group::HGROUP_REFERENCES.v) {
-        Printf(true, "%FtGROUP  %E%s", g->DescriptionString());
+        Printf(true, "%FtGROUP  %E%s", g->DescriptionString().c_str());
         goto list_items;
     } else {
         Printf(true, "%FtGROUP  %E%s [%Fl%Ll%D%frename%E/%Fl%Ll%D%fdel%E]",
-            g->DescriptionString(),
+            g->DescriptionString().c_str(),
             g->h.v, &TextWindow::ScreenChangeGroupName,
             g->h.v, &TextWindow::ScreenDeleteGroup);
     }
@@ -426,11 +425,11 @@ list_items:
         Request *r = &(SK.request.elem[i]);
 
         if(r->group.v == shown.group.v) {
-            char *s = r->DescriptionString();
+            std::string s = r->DescriptionString();
             Printf(false, "%Bp   %Fl%Ll%D%f%h%s%E",
                 (a & 1) ? 'd' : 'a',
                 r->h.v, (&TextWindow::ScreenSelectRequest),
-                &(TextWindow::ScreenHoverRequest), s);
+                &(TextWindow::ScreenHoverRequest), s.c_str());
             a++;
         }
     }
@@ -443,11 +442,11 @@ list_items:
         Constraint *c = &(SK.constraint.elem[i]);
 
         if(c->group.v == shown.group.v) {
-            char *s = c->DescriptionString();
+            std::string s = c->DescriptionString();
             Printf(false, "%Bp   %Fl%Ll%D%f%h%s%E %s",
                 (a & 1) ? 'd' : 'a',
                 c->h.v, (&TextWindow::ScreenSelectConstraint),
-                (&TextWindow::ScreenHoverConstraint), s,
+                (&TextWindow::ScreenHoverConstraint), s.c_str(),
                 c->reference ? "(ref)" : "");
             a++;
         }
@@ -469,7 +468,7 @@ void TextWindow::ShowGroupSolveInfo(void) {
         return;
     }
 
-    Printf(true, "%FtGROUP   %E%s", g->DescriptionString());
+    Printf(true, "%FtGROUP   %E%s", g->DescriptionString().c_str());
     switch(g->solved.how) {
         case System::DIDNT_CONVERGE:
             Printf(true, "%FxSOLVE FAILED!%Fd no convergence");
@@ -495,7 +494,7 @@ void TextWindow::ShowGroupSolveInfo(void) {
             (i & 1) ? 'd' : 'a',
             c->h.v, (&TextWindow::ScreenSelectConstraint),
             (&TextWindow::ScreenHoverConstraint),
-            c->DescriptionString());
+            c->DescriptionString().c_str());
     }
 
     Printf(true,  "It may be possible to fix the problem ");
@@ -509,19 +508,17 @@ void TextWindow::ShowGroupSolveInfo(void) {
 //-----------------------------------------------------------------------------
 void TextWindow::ScreenStepDimFinish(int link, uint32_t v) {
     SS.TW.edit.meaning = EDIT_STEP_DIM_FINISH;
-    char s[1024];
+    std::string edit_value;
     if(SS.TW.shown.dimIsDistance) {
-        strcpy(s, SS.MmToString(SS.TW.shown.dimFinish));
+        edit_value = SS.MmToString(SS.TW.shown.dimFinish);
     } else {
-        sprintf(s, "%.3f", SS.TW.shown.dimFinish);
+        edit_value = ssprintf("%.3f", SS.TW.shown.dimFinish);
     }
-    SS.TW.ShowEditControl(12, 12, s);
+    SS.TW.ShowEditControl(12, 12, edit_value);
 }
 void TextWindow::ScreenStepDimSteps(int link, uint32_t v) {
-    char str[1024];
-    sprintf(str, "%d", SS.TW.shown.dimSteps);
     SS.TW.edit.meaning = EDIT_STEP_DIM_STEPS;
-    SS.TW.ShowEditControl(14, 12, str);
+    SS.TW.ShowEditControl(14, 12, ssprintf("%d", SS.TW.shown.dimSteps));
 }
 void TextWindow::ScreenStepDimGo(int link, uint32_t v) {
     hConstraint hc = SS.TW.shown.constraint;
@@ -553,12 +550,12 @@ void TextWindow::ShowStepDimension(void) {
         return;
     }
 
-    Printf(true, "%FtSTEP DIMENSION%E %s", c->DescriptionString());
+    Printf(true, "%FtSTEP DIMENSION%E %s", c->DescriptionString().c_str());
 
     if(shown.dimIsDistance) {
-        Printf(true,  "%Ba   %Ftstart%E    %s", SS.MmToString(c->valA));
+        Printf(true,  "%Ba   %Ftstart%E    %s", SS.MmToString(c->valA).c_str());
         Printf(false, "%Bd   %Ftfinish%E   %s %Fl%Ll%f[change]%E",
-            SS.MmToString(shown.dimFinish), &ScreenStepDimFinish);
+            SS.MmToString(shown.dimFinish).c_str(), &ScreenStepDimFinish);
     } else {
         Printf(true,  "%Ba   %Ftstart%E    %@", c->valA);
         Printf(false, "%Bd   %Ftfinish%E   %@ %Fl%Ll%f[change]%E",
@@ -580,10 +577,8 @@ void TextWindow::ShowStepDimension(void) {
 void TextWindow::ScreenChangeTangentArc(int link, uint32_t v) {
     switch(link) {
         case 'r': {
-            char str[1024];
-            strcpy(str, SS.MmToString(SS.tangentArcRadius));
             SS.TW.edit.meaning = EDIT_TANGENT_ARC_RADIUS;
-            SS.TW.ShowEditControl(12, 3, str);
+            SS.TW.ShowEditControl(12, 3, SS.MmToString(SS.tangentArcRadius));
             break;
         }
 
@@ -597,7 +592,7 @@ void TextWindow::ShowTangentArc(void) {
     Printf(true,  "%Ft radius of created arc%E");
     if(SS.tangentArcManual) {
         Printf(false, "%Ba   %s %Fl%Lr%f[change]%E",
-            SS.MmToString(SS.tangentArcRadius),
+            SS.MmToString(SS.tangentArcRadius).c_str(),
             &(TextWindow::ScreenChangeTangentArc));
     } else {
         Printf(false, "%Ba   automatic");
@@ -671,7 +666,7 @@ void TextWindow::EditControlDone(const char *s) {
                 SS.UndoRemember();
 
                 Group *g = SK.GetGroup(edit.group);
-                g->name.strcpy(s);
+                g->name = s;
             }
             break;
         }
@@ -727,7 +722,7 @@ void TextWindow::EditControlDone(const char *s) {
             SS.UndoRemember();
             Request *r = SK.request.FindByIdNoOops(edit.request);
             if(r) {
-                r->str.strcpy(s);
+                r->str = s;
                 SS.MarkGroupDirty(r->group);
                 SS.ScheduleGenerateAll();
             }
diff --git a/src/textwin.cpp b/src/textwin.cpp
index b4a7c907..e20d2331 100644
--- a/src/textwin.cpp
+++ b/src/textwin.cpp
@@ -79,14 +79,14 @@ void TextWindow::HideEditControl(void) {
     HideTextEditControl();
 }
 
-void TextWindow::ShowEditControl(int halfRow, int col, char *s) {
+void TextWindow::ShowEditControl(int halfRow, int col, const std::string &str) {
     editControl.halfRow = halfRow;
     editControl.col = col;
 
     int x = LEFT_MARGIN + CHAR_WIDTH*col;
     int y = (halfRow - SS.TW.scrollPos)*(LINE_HEIGHT/2);
 
-    ShowTextEditControl(x - 3, y + 2, s);
+    ShowTextEditControl(x - 3, y + 2, str);
 }
 
 void TextWindow::ShowEditControlWithColorPicker(int halfRow, int col, RgbaColor rgb)
diff --git a/src/ttf.cpp b/src/ttf.cpp
index 129f7d17..4a7e0e25 100644
--- a/src/ttf.cpp
+++ b/src/ttf.cpp
@@ -26,7 +26,7 @@ void TtfFontList::LoadAll(void) {
     loaded = true;
 }
 
-void TtfFontList::PlotString(const std::string &font, char *str, double spacing,
+void TtfFontList::PlotString(const std::string &font, const char *str, double spacing,
                              SBezierList *sbl,
                              Vector origin, Vector u, Vector v)
 {
@@ -350,14 +350,11 @@ bool TtfFont::LoadFontFromFile(bool nameOnly) {
         if(nameOnly) {
             // Find the display name, and store it in the provided buffer.
             fseek(fh, nameAddr+nameStringOffset+displayNameOffset, SEEK_SET);
-            int c = 0;
+            name.clear();
             for(i = 0; i < displayNameLength; i++) {
-                uint8_t b = GetBYTE();
-                if(b && c < ((int)sizeof(name.str) - 2)) {
-                    name.str[c++] = b;
-                }
+                char b = (char)GetBYTE();
+                if(b) name += b;
             }
-            name.str[c++] = '\0';
 
             fclose(fh);
             return true;
@@ -673,7 +670,7 @@ void TtfFont::PlotCharacter(int *dx, int c, double spacing) {
     *dx = dx0 + g->advanceWidth + (int)(spacing + 0.5);
 }
 
-void TtfFont::PlotString(char *str, double spacing,
+void TtfFont::PlotString(const char *str, double spacing,
                          SBezierList *sbl,
                          Vector porigin, Vector pu, Vector pv)
 {
diff --git a/src/ui.h b/src/ui.h
index ed73f780..705a2e8d 100644
--- a/src/ui.h
+++ b/src/ui.h
@@ -208,7 +208,7 @@ public:
     } editControl;
 
     void HideEditControl(void);
-    void ShowEditControl(int halfRow, int col, char *s);
+    void ShowEditControl(int halfRow, int col, const std::string &str);
     void ShowEditControlWithColorPicker(int halfRow, int col, RgbaColor rgb);
 
     void ClearSuper(void);
diff --git a/src/util.cpp b/src/util.cpp
index 633b15bc..959026cb 100644
--- a/src/util.cpp
+++ b/src/util.cpp
@@ -6,6 +6,25 @@
 //-----------------------------------------------------------------------------
 #include "solvespace.h"
 
+std::string SolveSpace::ssprintf(const char *fmt, ...)
+{
+    va_list va;
+
+    va_start(va, fmt);
+    int size = vsnprintf(NULL, 0, fmt, va);
+    if(size < 0) oops();
+    va_end(va);
+
+    std::string result;
+    result.resize(size);
+
+    va_start(va, fmt);
+    vsnprintf(&result[0], size + 1, fmt, va);
+    va_end(va);
+
+    return result;
+}
+
 // See https://github.com/GNOME/glibmm/blob/2fbd9f23/glib/glibmm/ustring.cc#L227
 const char *SolveSpace::ReadUTF8(const char *str, char32_t *result)
 {
diff --git a/src/view.cpp b/src/view.cpp
index ed2858c2..0ce5cd34 100644
--- a/src/view.cpp
+++ b/src/view.cpp
@@ -18,9 +18,9 @@ void TextWindow::ShowEditView(void) {
 
     Printf(false, "%Bd %Ftorigin (maps to center of screen)%E");
     Printf(false, "%Ba   (%s, %s, %s) %Fl%Ll%f[edit]%E",
-        SS.MmToString(-SS.GW.offset.x),
-        SS.MmToString(-SS.GW.offset.y),
-        SS.MmToString(-SS.GW.offset.z),
+        SS.MmToString(-SS.GW.offset.x).c_str(),
+        SS.MmToString(-SS.GW.offset.y).c_str(),
+        SS.MmToString(-SS.GW.offset.z).c_str(),
         &ScreenChangeViewOrigin);
     Printf(false, "");
 
@@ -38,29 +38,26 @@ void TextWindow::ShowEditView(void) {
 }
 
 void TextWindow::ScreenChangeViewScale(int link, uint32_t v) {
-    char buf[1024];
-    sprintf(buf, "%.3f", SS.GW.scale * SS.MmPerUnit());
-
     SS.TW.edit.meaning = EDIT_VIEW_SCALE;
-    SS.TW.ShowEditControl(12, 3, buf);
+    SS.TW.ShowEditControl(12, 3, ssprintf("%.3f", SS.GW.scale * SS.MmPerUnit()));
 }
 
 void TextWindow::ScreenChangeViewOrigin(int link, uint32_t v) {
-    char buf[1024];
-    sprintf(buf, "%s, %s, %s",
-        SS.MmToString(-SS.GW.offset.x),
-        SS.MmToString(-SS.GW.offset.y),
-        SS.MmToString(-SS.GW.offset.z));
+    std::string edit_value =
+        ssprintf("%s, %s, %s",
+            SS.MmToString(-SS.GW.offset.x).c_str(),
+            SS.MmToString(-SS.GW.offset.y).c_str(),
+            SS.MmToString(-SS.GW.offset.z).c_str());
 
     SS.TW.edit.meaning = EDIT_VIEW_ORIGIN;
-    SS.TW.ShowEditControl(18, 3, buf);
+    SS.TW.ShowEditControl(18, 3, edit_value);
 }
 
 void TextWindow::ScreenChangeViewProjection(int link, uint32_t v) {
-    char buf[1024];
-    sprintf(buf, "%.3f, %.3f, %.3f", CO(SS.GW.projRight));
+    std::string edit_value =
+        ssprintf("%.3f, %.3f, %.3f", CO(SS.GW.projRight));
     SS.TW.edit.meaning = EDIT_VIEW_PROJ_RIGHT;
-    SS.TW.ShowEditControl(24, 10, buf);
+    SS.TW.ShowEditControl(24, 10, edit_value);
 }
 
 bool TextWindow::EditControlDoneForView(const char *s) {
diff --git a/src/win32/w32main.cpp b/src/win32/w32main.cpp
index fe9f64e3..702f5682 100644
--- a/src/win32/w32main.cpp
+++ b/src/win32/w32main.cpp
@@ -812,11 +812,11 @@ static void ShowEditControl(HWND h, int x, int y, const std::wstring &s) {
         SetFocus(h);
     }
 }
-void SolveSpace::ShowTextEditControl(int x, int y, char *s)
+void SolveSpace::ShowTextEditControl(int x, int y, const std::string &str)
 {
     if(GraphicsEditControlIsVisible()) return;
 
-    ShowEditControl(TextEditControl, x, y, Widen(s));
+    ShowEditControl(TextEditControl, x, y, Widen(str));
 }
 void SolveSpace::HideTextEditControl(void)
 {
@@ -826,7 +826,7 @@ bool SolveSpace::TextEditControlIsVisible(void)
 {
     return IsWindowVisible(TextEditControl) ? true : false;
 }
-void SolveSpace::ShowGraphicsEditControl(int x, int y, char *s)
+void SolveSpace::ShowGraphicsEditControl(int x, int y, const std::string &str)
 {
     if(GraphicsEditControlIsVisible()) return;
 
@@ -839,7 +839,7 @@ void SolveSpace::ShowGraphicsEditControl(int x, int y, char *s)
     // top left corner
     y -= 20;
 
-    ShowEditControl(GraphicsEditControl, x, y, Widen(s));
+    ShowEditControl(GraphicsEditControl, x, y, Widen(str));
 }
 void SolveSpace::HideGraphicsEditControl(void)
 {