Run clang-tidy’s modernize-deprecated-headers pass.

This renames most C <*.h> includes into C++ <c*> includes.

119 files changed, 162 insertions, 162 deletions

diff --git a/src/cms-color-types.h b/src/cms-color-types.h
index 0a49a1d21..2d75373eb 100644
--- a/src/cms-color-types.h
+++ b/src/cms-color-types.h
@@ -15,7 +15,7 @@
 #endif
 
 #if HAVE_STDINT_H
-# include <stdint.h> // uint8_t, etc
+# include <cstdint> // uint8_t, etc
 #endif
 typedef unsigned int guint32;
 
diff --git a/src/colorspace.h b/src/colorspace.h
index 9b7af55e5..52fc7d63c 100644
--- a/src/colorspace.h
+++ b/src/colorspace.h
@@ -15,7 +15,7 @@
 #endif // HAVE_CONFIG_H
 
 #if HAVE_STDINT_H
-# include <stdint.h>
+# include <cstdint>
 #endif
 
 #include <vector>
diff --git a/src/conn-avoid-ref.h b/src/conn-avoid-ref.h
index 2c7da9aae..d304a95cc 100644
--- a/src/conn-avoid-ref.h
+++ b/src/conn-avoid-ref.h
@@ -14,7 +14,7 @@
  */
 
 #include <2geom/point.h>
-#include <stddef.h>
+#include <cstddef>
 #include <sigc++/connection.h>
 
 class  SPDesktop;
diff --git a/src/debug/demangle.cpp b/src/debug/demangle.cpp
index 04fe80d9b..a5f868a76 100644
--- a/src/debug/demangle.cpp
+++ b/src/debug/demangle.cpp
@@ -9,8 +9,8 @@
  * Released under GNU GPL, read the file 'COPYING' for more information
  */
 
-#include <stdio.h>
-#include <string.h>
+#include <cstdio>
+#include <cstring>
 #include <map>
 #include "debug/demangle.h"
 #include "util/format.h"
diff --git a/src/debug/simple-event.h b/src/debug/simple-event.h
index 7f7f7614d..7870ca0d1 100644
--- a/src/debug/simple-event.h
+++ b/src/debug/simple-event.h
@@ -12,7 +12,7 @@
 #ifndef SEEN_INKSCAPE_DEBUG_SIMPLE_EVENT_H
 #define SEEN_INKSCAPE_DEBUG_SIMPLE_EVENT_H
 
-#include <stdarg.h>
+#include <cstdarg>
 #include <vector>
 #include <glib.h> // g_assert()
 
diff --git a/src/desktop.h b/src/desktop.h
index 927e1a3da..9de4c0e14 100644
--- a/src/desktop.h
+++ b/src/desktop.h
@@ -25,7 +25,7 @@
 #include "config.h"
 #endif
 
-#include <stddef.h>
+#include <cstddef>
 #include <sigc++/sigc++.h>
 
 #include <2geom/affine.h>
diff --git a/src/dir-util.cpp b/src/dir-util.cpp
index 96968cd6d..1a215fa29 100644
--- a/src/dir-util.cpp
+++ b/src/dir-util.cpp
@@ -3,7 +3,7 @@
  * Utility functions for filenames.
  */
 
-#include <errno.h>
+#include <cerrno>
 #include <string>
 #include <cstring>
 #include <glib.h>
diff --git a/src/display/cairo-templates.h b/src/display/cairo-templates.h
index a49f925c3..ba2213e0b 100644
--- a/src/display/cairo-templates.h
+++ b/src/display/cairo-templates.h
@@ -27,7 +27,7 @@ static const int OPENMP_THRESHOLD = 2048;
 
 #include <algorithm>
 #include <cairo.h>
-#include <math.h>
+#include <cmath>
 #include "display/nr-3dutils.h"
 #include "display/cairo-utils.h"
 
diff --git a/src/display/canvas-bpath.cpp b/src/display/canvas-bpath.cpp
index 35f46e2ae..b12e617f5 100644
--- a/src/display/canvas-bpath.cpp
+++ b/src/display/canvas-bpath.cpp
@@ -12,7 +12,7 @@
  */
 
 #include <sstream>
-#include <string.h>
+#include <cstring>
 #include "desktop.h"
 
 #include "color.h"
diff --git a/src/display/canvas-text.cpp b/src/display/canvas-text.cpp
index 9df002f7f..25a0f56a0 100644
--- a/src/display/canvas-text.cpp
+++ b/src/display/canvas-text.cpp
@@ -13,7 +13,7 @@
  */
 
 #include <sstream>
-#include <string.h>
+#include <cstring>
 
 #include "sp-canvas-util.h"
 #include "canvas-text.h"
diff --git a/src/display/nr-filter-colormatrix.cpp b/src/display/nr-filter-colormatrix.cpp
index e50536ff5..d27e6104a 100644
--- a/src/display/nr-filter-colormatrix.cpp
+++ b/src/display/nr-filter-colormatrix.cpp
@@ -10,7 +10,7 @@
  * Released under GNU GPL, read the file 'COPYING' for more information
  */
 
-#include <math.h>
+#include <cmath>
 #include <algorithm>
 #include "display/cairo-templates.h"
 #include "display/cairo-utils.h"
diff --git a/src/display/nr-filter-component-transfer.cpp b/src/display/nr-filter-component-transfer.cpp
index e796d1792..38b66e230 100644
--- a/src/display/nr-filter-component-transfer.cpp
+++ b/src/display/nr-filter-component-transfer.cpp
@@ -10,7 +10,7 @@
  * Released under GNU GPL, read the file 'COPYING' for more information
  */
 
-#include <math.h>
+#include <cmath>
 #include "display/cairo-templates.h"
 #include "display/cairo-utils.h"
 #include "display/nr-filter-component-transfer.h"
diff --git a/src/display/nr-filter-slot.cpp b/src/display/nr-filter-slot.cpp
index 1358530b8..3b7a653dd 100644
--- a/src/display/nr-filter-slot.cpp
+++ b/src/display/nr-filter-slot.cpp
@@ -11,8 +11,8 @@
  * Released under GNU GPL, read the file 'COPYING' for more information
  */
 
-#include <assert.h>
-#include <string.h>
+#include <cassert>
+#include <cstring>
 
 #include <2geom/transforms.h>
 #include "display/cairo-utils.h"
diff --git a/src/display/nr-filter-turbulence.cpp b/src/display/nr-filter-turbulence.cpp
index 349bcc242..2c7668631 100644
--- a/src/display/nr-filter-turbulence.cpp
+++ b/src/display/nr-filter-turbulence.cpp
@@ -23,7 +23,7 @@
 #include "display/nr-filter-turbulence.h"
 #include "display/nr-filter-units.h"
 #include "display/nr-filter-utils.h"
-#include <math.h>
+#include <cmath>
 
 namespace Inkscape {
 namespace Filters{
diff --git a/src/display/sp-canvas.h b/src/display/sp-canvas.h
index d30e0a485..4e9a81d83 100644
--- a/src/display/sp-canvas.h
+++ b/src/display/sp-canvas.h
@@ -25,7 +25,7 @@
 #endif
 
 #include <gtk/gtk.h>
-#include <stdint.h>
+#include <cstdint>
 #include <glibmm/ustring.h>
 #include <2geom/affine.h>
 #include <2geom/rect.h>
diff --git a/src/document-private.h b/src/document-private.h
index 6ca36ac1a..a9b70714f 100644
--- a/src/document-private.h
+++ b/src/document-private.h
@@ -17,7 +17,7 @@
 #include <map>
 #include <set>
 #include <string>
-#include <stddef.h>
+#include <cstddef>
 #include <sigc++/sigc++.h>
 #include "xml/event-fns.h"
 #include "document.h"
diff --git a/src/document-subset.h b/src/document-subset.h
index b0a17eff5..9c1996795 100644
--- a/src/document-subset.h
+++ b/src/document-subset.h
@@ -10,7 +10,7 @@
 #ifndef SEEN_INKSCAPE_DOCUMENT_SUBSET_H
 #define SEEN_INKSCAPE_DOCUMENT_SUBSET_H
 
-#include <stddef.h>
+#include <cstddef>
 #include <sigc++/connection.h>
 #include <sigc++/functors/slot.h>
 
diff --git a/src/document.h b/src/document.h
index 053137ffd..251aa8619 100644
--- a/src/document.h
+++ b/src/document.h
@@ -17,7 +17,7 @@
  * Released under GNU GPL, read the file 'COPYING' for more information
  */
 
-#include <stddef.h>
+#include <cstddef>
 #include <sigc++/sigc++.h>
 #include "3rdparty/libcroco/cr-cascade.h"
 #include <2geom/forward.h>
diff --git a/src/ege-color-prof-tracker.cpp b/src/ege-color-prof-tracker.cpp
index d709f60f9..f4a1e46df 100644
--- a/src/ege-color-prof-tracker.cpp
+++ b/src/ege-color-prof-tracker.cpp
@@ -39,7 +39,7 @@
 
 /* Note: this file should be kept compilable as both .cpp and .c */
 
-#include <string.h>
+#include <cstring>
 #include <vector>
 #include <algorithm>
 
diff --git a/src/extension/implementation/script.cpp b/src/extension/implementation/script.cpp
index 90269c557..72a015b57 100644
--- a/src/extension/implementation/script.cpp
+++ b/src/extension/implementation/script.cpp
@@ -21,7 +21,7 @@
 #include <glibmm/convert.h>
 #include <unistd.h>
 
-#include <errno.h>
+#include <cerrno>
 #include <glib/gstdio.h>
 
 
diff --git a/src/extension/internal/cairo-render-context.cpp b/src/extension/internal/cairo-render-context.cpp
index 36f73136b..969fff4f9 100644
--- a/src/extension/internal/cairo-render-context.cpp
+++ b/src/extension/internal/cairo-render-context.cpp
@@ -25,11 +25,11 @@
 #endif
 
 
-#include <signal.h>
-#include <limits.h>
-#include <errno.h>
-#include <time.h>
-#include <stdlib.h>
+#include <csignal>
+#include <climits>
+#include <cerrno>
+#include <ctime>
+#include <cstdlib>
 #include <2geom/pathvector.h>
 
 #include <glib.h>
diff --git a/src/extension/internal/cairo-renderer.cpp b/src/extension/internal/cairo-renderer.cpp
index eca17966e..c7cd35eb2 100644
--- a/src/extension/internal/cairo-renderer.cpp
+++ b/src/extension/internal/cairo-renderer.cpp
@@ -25,8 +25,8 @@
 #endif
 
 
-#include <signal.h>
-#include <errno.h>
+#include <csignal>
+#include <cerrno>
 
 #include "libnrtype/Layout-TNG.h"
 #include <2geom/transforms.h>
diff --git a/src/extension/internal/cdr-input.cpp b/src/extension/internal/cdr-input.cpp
index e1f67dc85..5f42c1a94 100644
--- a/src/extension/internal/cdr-input.cpp
+++ b/src/extension/internal/cdr-input.cpp
@@ -13,7 +13,7 @@
  *
  */
 
-#include <stdio.h>
+#include <cstdio>
 #include "config.h"
 
 #include "cdr-input.h"
diff --git a/src/extension/internal/emf-inout.cpp b/src/extension/internal/emf-inout.cpp
index f8cedcb50..549d4300e 100644
--- a/src/extension/internal/emf-inout.cpp
+++ b/src/extension/internal/emf-inout.cpp
@@ -27,9 +27,9 @@
 # include "config.h"
 #endif
 
-#include <stdio.h>
-#include <stdlib.h>
-#include <stdint.h>
+#include <cstdio>
+#include <cstdlib>
+#include <cstdint>
 #include <3rdparty/libuemf/symbol_convert.h>
 
 #include "document.h"
diff --git a/src/extension/internal/emf-print.cpp b/src/extension/internal/emf-print.cpp
index ec4594eea..548caea95 100644
--- a/src/extension/internal/emf-print.cpp
+++ b/src/extension/internal/emf-print.cpp
@@ -26,7 +26,7 @@
 # include "config.h"
 #endif
 
-#include <string.h>
+#include <cstring>
 #include <glibmm/miscutils.h>
 #include <3rdparty/libuemf/symbol_convert.h>
 #include <2geom/sbasis-to-bezier.h>
diff --git a/src/extension/internal/image-resolution.cpp b/src/extension/internal/image-resolution.cpp
index e5b1e4619..e16487f8e 100644
--- a/src/extension/internal/image-resolution.cpp
+++ b/src/extension/internal/image-resolution.cpp
@@ -27,7 +27,7 @@
 #ifdef HAVE_JPEG
 #define IR_TRY_JFIF 1
 #include <jpeglib.h>
-#include <setjmp.h>
+#include <csetjmp>
 #endif
 
 #ifdef WITH_IMAGE_MAGICK
diff --git a/src/extension/internal/javafx-out.cpp b/src/extension/internal/javafx-out.cpp
index 5646eeefd..0185e07cd 100644
--- a/src/extension/internal/javafx-out.cpp
+++ b/src/extension/internal/javafx-out.cpp
@@ -43,8 +43,8 @@
 #include "style.h"
 
 #include <string>
-#include <stdio.h>
-#include <stdarg.h>
+#include <cstdio>
+#include <cstdarg>
 #include "extension/extension.h"
 
 
diff --git a/src/extension/internal/latex-pstricks.cpp b/src/extension/internal/latex-pstricks.cpp
index aa90c4f59..226f915aa 100644
--- a/src/extension/internal/latex-pstricks.cpp
+++ b/src/extension/internal/latex-pstricks.cpp
@@ -18,8 +18,8 @@
 #include <2geom/pathvector.h>
 #include <2geom/sbasis-to-bezier.h>
 #include <2geom/curves.h>
-#include <errno.h>
-#include <signal.h>
+#include <cerrno>
+#include <csignal>
 #include "util/units.h"
 #include "helper/geom-curves.h"
 
diff --git a/src/extension/internal/latex-text-renderer.cpp b/src/extension/internal/latex-text-renderer.cpp
index c61a95922..fe9e78bf2 100644
--- a/src/extension/internal/latex-text-renderer.cpp
+++ b/src/extension/internal/latex-text-renderer.cpp
@@ -21,8 +21,8 @@
 
 #include "latex-text-renderer.h"
 
-#include <signal.h>
-#include <errno.h>
+#include <csignal>
+#include <cerrno>
 
 #include "libnrtype/Layout-TNG.h"
 #include <2geom/transforms.h>
diff --git a/src/extension/internal/metafile-inout.h b/src/extension/internal/metafile-inout.h
index d3e870a25..eaa8334ee 100644
--- a/src/extension/internal/metafile-inout.h
+++ b/src/extension/internal/metafile-inout.h
@@ -17,9 +17,9 @@
 
 #define PNG_SKIP_SETJMP_CHECK // else any further png.h include blows up in the compiler
 #include <png.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <stdint.h>
+#include <cstdio>
+#include <cstdlib>
+#include <cstdint>
 #include <map>
 #include <stack>
 #include <glibmm/ustring.h>
diff --git a/src/extension/internal/odf.cpp b/src/extension/internal/odf.cpp
index 2c25ea1f4..18092873e 100644
--- a/src/extension/internal/odf.cpp
+++ b/src/extension/internal/odf.cpp
@@ -44,10 +44,10 @@
 #include "odf.h"
 
 //# System includes
-#include <stdio.h>
-#include <time.h>
+#include <cstdio>
+#include <ctime>
 #include <vector>
-#include <math.h>
+#include <cmath>
 
 //# Inkscape includes
 #include "clear-n_.h"
@@ -101,7 +101,7 @@ typedef Inkscape::IO::StringOutputStream StringOutputStream;
 //########################################################################
 //# C L A S S    SingularValueDecomposition
 //########################################################################
-#include <math.h>
+#include <cmath>
 
 class SVDMatrix
 {
diff --git a/src/extension/internal/pdfinput/pdf-parser.cpp b/src/extension/internal/pdfinput/pdf-parser.cpp
index fbcb708fe..fcefcd059 100644
--- a/src/extension/internal/pdfinput/pdf-parser.cpp
+++ b/src/extension/internal/pdfinput/pdf-parser.cpp
@@ -23,11 +23,11 @@
 
 extern "C" {
         
-#include <stdlib.h>
-#include <stdio.h>
-#include <stddef.h>
-#include <string.h>
-#include <math.h>
+#include <cstdlib>
+#include <cstdio>
+#include <cstddef>
+#include <cstring>
+#include <cmath>
 
 }
 
diff --git a/src/extension/internal/pov-out.cpp b/src/extension/internal/pov-out.cpp
index 2215fbb3e..0cfeeff94 100644
--- a/src/extension/internal/pov-out.cpp
+++ b/src/extension/internal/pov-out.cpp
@@ -38,8 +38,8 @@
 #include "style.h"
 
 #include <string>
-#include <stdio.h>
-#include <stdarg.h>
+#include <cstdio>
+#include <cstdarg>
 #include "document.h"
 #include "extension/extension.h"
 
diff --git a/src/extension/internal/vsd-input.cpp b/src/extension/internal/vsd-input.cpp
index e4982a02c..46aa0245c 100644
--- a/src/extension/internal/vsd-input.cpp
+++ b/src/extension/internal/vsd-input.cpp
@@ -13,7 +13,7 @@
  *
  */
 
-#include <stdio.h>
+#include <cstdio>
 #include "config.h"
 
 #include "vsd-input.h"
diff --git a/src/extension/internal/wmf-inout.cpp b/src/extension/internal/wmf-inout.cpp
index 5941aaf1e..db7c9c9ce 100644
--- a/src/extension/internal/wmf-inout.cpp
+++ b/src/extension/internal/wmf-inout.cpp
@@ -28,9 +28,9 @@
 #endif
 
 //#include <png.h>   //This must precede text_reassemble.h or it blows up in pngconf.h when compiling
-#include <stdio.h>
-#include <stdlib.h>
-#include <stdint.h>
+#include <cstdio>
+#include <cstdlib>
+#include <cstdint>
 #include <3rdparty/libuemf/symbol_convert.h>
 
 #include "document.h"
diff --git a/src/extension/internal/wmf-print.cpp b/src/extension/internal/wmf-print.cpp
index d98d28b09..6c431eba5 100644
--- a/src/extension/internal/wmf-print.cpp
+++ b/src/extension/internal/wmf-print.cpp
@@ -63,7 +63,7 @@
 
 #include "wmf-print.h"
 
-#include <string.h>
+#include <cstring>
 #include <3rdparty/libuemf/symbol_convert.h>
 
 namespace Inkscape {
diff --git a/src/extension/internal/wpg-input.cpp b/src/extension/internal/wpg-input.cpp
index 0953e5696..6a790ed4c 100644
--- a/src/extension/internal/wpg-input.cpp
+++ b/src/extension/internal/wpg-input.cpp
@@ -39,7 +39,7 @@
  * Corel Corporation or Corel Corporation Limited."
  */
 
-#include <stdio.h>
+#include <cstdio>
 #include "config.h"
 
 #ifdef WITH_LIBWPG
diff --git a/src/extension/loader.cpp b/src/extension/loader.cpp
index 7761b79bd..9d8c52aea 100644
--- a/src/extension/loader.cpp
+++ b/src/extension/loader.cpp
@@ -14,7 +14,7 @@
 #include <gmodule.h>
 
 #include "system.h"
-#include <string.h>
+#include <cstring>
 #include "dependency.h"
 #include "inkscape-version.h"
 
diff --git a/src/extension/timer.h b/src/extension/timer.h
index b257c770a..e00929013 100644
--- a/src/extension/timer.h
+++ b/src/extension/timer.h
@@ -13,7 +13,7 @@
 #ifndef INKSCAPE_EXTENSION_TIMER_H__
 #define INKSCAPE_EXTENSION_TIMER_H__
 
-#include <stddef.h>
+#include <cstddef>
 #include <sigc++/sigc++.h>
 #include <glibmm/timeval.h>
 
diff --git a/src/extract-uri.cpp b/src/extract-uri.cpp
index ae2efcb0e..e640e530d 100644
--- a/src/extract-uri.cpp
+++ b/src/extract-uri.cpp
@@ -1,4 +1,4 @@
-#include <string.h>
+#include <cstring>
 #include <glib.h>
 
 #include "extract-uri.h"
diff --git a/src/gradient-drag.h b/src/gradient-drag.h
index 3e9e7a151..691fb0553 100644
--- a/src/gradient-drag.h
+++ b/src/gradient-drag.h
@@ -17,7 +17,7 @@
  * Released under GNU GPL, read the file 'COPYING' for more information
  */
 
-#include <stddef.h>
+#include <cstddef>
 #include <sigc++/sigc++.h>
 #include <vector>
 #include <set>
diff --git a/src/inkscape.cpp b/src/inkscape.cpp
index 2a2fa4f86..c5089b633 100644
--- a/src/inkscape.cpp
+++ b/src/inkscape.cpp
@@ -18,7 +18,7 @@
 #include <config.h>
 #endif
 
-#include <errno.h>
+#include <cerrno>
 
 #include <map>
 
diff --git a/src/io/http.cpp b/src/io/http.cpp
index c081ca7bc..c12cf079a 100644
--- a/src/io/http.cpp
+++ b/src/io/http.cpp
@@ -35,7 +35,7 @@
 #include <glib/gstdio.h>
 #include <libsoup/soup.h>
 #include <string>
-#include <time.h>
+#include <ctime>
 
 #include "io/sys.h"
 #include "io/http.h"
diff --git a/src/io/sys.h b/src/io/sys.h
index e349fc09c..39ba399f5 100644
--- a/src/io/sys.h
+++ b/src/io/sys.h
@@ -12,7 +12,7 @@
  * Released under GNU GPL, read the file 'COPYING' for more information
  */
 
-#include <stdio.h>
+#include <cstdio>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <glib.h>
diff --git a/src/livarot/AlphaLigne.cpp b/src/livarot/AlphaLigne.cpp
index c7e7487bd..2c969107a 100644
--- a/src/livarot/AlphaLigne.cpp
+++ b/src/livarot/AlphaLigne.cpp
@@ -9,9 +9,9 @@
 
 #include "AlphaLigne.h"
 
-#include <math.h>
-#include <stdio.h>
-#include <stdlib.h>
+#include <cmath>
+#include <cstdio>
+#include <cstdlib>
 #include <glib.h>
 
 AlphaLigne::AlphaLigne(int iMin,int iMax)
diff --git a/src/livarot/BitLigne.cpp b/src/livarot/BitLigne.cpp
index d7cce26eb..e868d6374 100644
--- a/src/livarot/BitLigne.cpp
+++ b/src/livarot/BitLigne.cpp
@@ -9,7 +9,7 @@
 
 #include "BitLigne.h"
 
-#include <math.h>
+#include <cmath>
 #include <cstring>
 #include <cstdlib>
 #include <string>
diff --git a/src/livarot/LivarotDefs.h b/src/livarot/LivarotDefs.h
index d020841b0..aa1919cf1 100644
--- a/src/livarot/LivarotDefs.h
+++ b/src/livarot/LivarotDefs.h
@@ -13,7 +13,7 @@
 # include "config.h"
 #endif
 
-#include <stdint.h>
+#include <cstdint>
 
 // error codes (mostly obsolete)
 enum
diff --git a/src/livarot/float-line.cpp b/src/livarot/float-line.cpp
index aa2db08fc..b0b36cf52 100644
--- a/src/livarot/float-line.cpp
+++ b/src/livarot/float-line.cpp
@@ -12,7 +12,7 @@
 #ifdef faster_flatten
 # include <cmath>  // std::abs(float)
 #endif
-#include <stdio.h>
+#include <cstdio>
 #include "livarot/float-line.h"
 #include "livarot/int-line.h"
 #include <cstdio>
diff --git a/src/live_effects/effect.cpp b/src/live_effects/effect.cpp
index 6251740d5..1eb08a0e8 100644
--- a/src/live_effects/effect.cpp
+++ b/src/live_effects/effect.cpp
@@ -86,8 +86,8 @@
 #include "object/sp-defs.h"
 #include "object/sp-shape.h"
 
-#include <stdio.h>
-#include <string.h>
+#include <cstdio>
+#include <cstring>
 #include <pangomm/layout.h>
 #include <gtkmm/expander.h>
 
diff --git a/src/live_effects/lpe-attach-path.cpp b/src/live_effects/lpe-attach-path.cpp
index 9ab832c5e..c50341f79 100644
--- a/src/live_effects/lpe-attach-path.cpp
+++ b/src/live_effects/lpe-attach-path.cpp
@@ -4,7 +4,7 @@
  * Released under GNU GPL, read the file 'COPYING' for more information
  */
 
-#include <math.h>
+#include <cmath>
 #include "live_effects/lpe-attach-path.h"
 #include "display/curve.h"
 #include "2geom/path-sink.h"
diff --git a/src/live_effects/lpe-bool.cpp b/src/live_effects/lpe-bool.cpp
index eb8918555..a76463742 100644
--- a/src/live_effects/lpe-bool.cpp
+++ b/src/live_effects/lpe-bool.cpp
@@ -7,8 +7,8 @@
  */
 
 #include <glibmm/i18n.h>
-#include <math.h>
-#include <string.h>
+#include <cmath>
+#include <cstring>
 #include <algorithm>
 
 #include "live_effects/lpe-bool.h"
diff --git a/src/live_effects/lpeobject-reference.cpp b/src/live_effects/lpeobject-reference.cpp
index 14472d001..e430c12f1 100644
--- a/src/live_effects/lpeobject-reference.cpp
+++ b/src/live_effects/lpeobject-reference.cpp
@@ -8,7 +8,7 @@
 
 #include "live_effects/lpeobject-reference.h"
 
-#include <string.h>
+#include <cstring>
 
 #include "bad-uri-exception.h"
 #include "live_effects/lpeobject.h"
diff --git a/src/live_effects/parameter/item.h b/src/live_effects/parameter/item.h
index dca7f7cb6..1c285fcff 100644
--- a/src/live_effects/parameter/item.h
+++ b/src/live_effects/parameter/item.h
@@ -14,7 +14,7 @@
 
 #include "live_effects/parameter/parameter.h"
 #include "live_effects/parameter/item-reference.h"
-#include <stddef.h>
+#include <cstddef>
 #include <sigc++/sigc++.h>
 
 namespace Inkscape {
diff --git a/src/live_effects/parameter/path.h b/src/live_effects/parameter/path.h
index 97f97d3dd..5993b54e6 100644
--- a/src/live_effects/parameter/path.h
+++ b/src/live_effects/parameter/path.h
@@ -14,7 +14,7 @@
 
 #include "live_effects/parameter/parameter.h"
 #include "live_effects/parameter/path-reference.h"
-#include <stddef.h>
+#include <cstddef>
 #include <sigc++/sigc++.h>
 
 namespace Inkscape {
diff --git a/src/live_effects/spiro.cpp b/src/live_effects/spiro.cpp
index a2ff4813e..c0e314a69 100644
--- a/src/live_effects/spiro.cpp
+++ b/src/live_effects/spiro.cpp
@@ -24,9 +24,9 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 
 #include "spiro.h"
 
-#include <math.h>
-#include <stdlib.h>
-#include <string.h>
+#include <cmath>
+#include <cstdlib>
+#include <cstring>
 
 #include "display/curve.h"
 
diff --git a/src/main.cpp b/src/main.cpp
index ee5735e02..88a1392b8 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -119,7 +119,7 @@
 #include "main-cmdlineact.h"
 #include "main-cmdlinexact.h"
 
-#include <errno.h>
+#include <cerrno>
 #include "verbs.h"
 
 #include "path-chemistry.h"
diff --git a/src/message-stack.cpp b/src/message-stack.cpp
index fdc08f4aa..9fc3045b2 100644
--- a/src/message-stack.cpp
+++ b/src/message-stack.cpp
@@ -9,7 +9,7 @@
  * Released under GNU GPL, read the file 'COPYING' for more information
  */
 
-#include <string.h>
+#include <cstring>
 #include <glib.h>
 #include <cstring>
 #include "message-stack.h"
diff --git a/src/mod360.cpp b/src/mod360.cpp
index ce5cea33a..6a5ce3d20 100644
--- a/src/mod360.cpp
+++ b/src/mod360.cpp
@@ -1,5 +1,5 @@
 #include <glib.h>
-#include <math.h>
+#include <cmath>
 
 #include "mod360.h"
 
@@ -9,7 +9,7 @@
 double mod360(double const x)
 {
     double const m = fmod(x, 360.0);
-    double const ret = ( isnan(m)
+    double const ret = ( std::isnan(m)
                          ? 0.0
                          : ( m < 0
                              ? m + 360
diff --git a/src/object/filters/blend.cpp b/src/object/filters/blend.cpp
index 400520e5b..33fa56506 100644
--- a/src/object/filters/blend.cpp
+++ b/src/object/filters/blend.cpp
@@ -13,7 +13,7 @@
  * Released under GNU GPL, read the file 'COPYING' for more information
  */
 
-#include <string.h>
+#include <cstring>
 
 #include "blend.h"
 
diff --git a/src/object/filters/colormatrix.cpp b/src/object/filters/colormatrix.cpp
index 4f4498e32..0017fa0b2 100644
--- a/src/object/filters/colormatrix.cpp
+++ b/src/object/filters/colormatrix.cpp
@@ -14,7 +14,7 @@
  * Released under GNU GPL, read the file 'COPYING' for more information
  */
 
-#include <string.h>
+#include <cstring>
 
 #include "attributes.h"
 #include "svg/svg.h"
diff --git a/src/object/filters/convolvematrix.cpp b/src/object/filters/convolvematrix.cpp
index 2466fe396..0f9c993f6 100644
--- a/src/object/filters/convolvematrix.cpp
+++ b/src/object/filters/convolvematrix.cpp
@@ -13,8 +13,8 @@
  * Released under GNU GPL, read the file 'COPYING' for more information
  */
 
-#include <string.h>
-#include <math.h>
+#include <cstring>
+#include <cmath>
 #include <vector>
 
 #include "convolvematrix.h"
diff --git a/src/object/filters/morphology.cpp b/src/object/filters/morphology.cpp
index ee7b1eaaa..830240049 100644
--- a/src/object/filters/morphology.cpp
+++ b/src/object/filters/morphology.cpp
@@ -13,7 +13,7 @@
  * Released under GNU GPL, read the file 'COPYING' for more information
  */
 
-#include <string.h>
+#include <cstring>
 
 #include "attributes.h"
 #include "svg/svg.h"
diff --git a/src/object/filters/sp-filter-primitive.cpp b/src/object/filters/sp-filter-primitive.cpp
index f418bcb4e..1f314c827 100644
--- a/src/object/filters/sp-filter-primitive.cpp
+++ b/src/object/filters/sp-filter-primitive.cpp
@@ -17,7 +17,7 @@
 #include <config.h>
 #endif
 
-#include <string.h>
+#include <cstring>
 
 #include "sp-filter-primitive.h"
 
diff --git a/src/object/sp-filter.cpp b/src/object/sp-filter.cpp
index 5668061ba..eaddfdcbf 100644
--- a/src/object/sp-filter.cpp
+++ b/src/object/sp-filter.cpp
@@ -20,7 +20,7 @@
 #include "sp-filter.h"
 
 #include <map>
-#include <string.h>
+#include <cstring>
 
 #include <glibmm.h>
 
diff --git a/src/object/sp-hatch-path.h b/src/object/sp-hatch-path.h
index ca00ae79d..228628f2e 100644
--- a/src/object/sp-hatch-path.h
+++ b/src/object/sp-hatch-path.h
@@ -16,7 +16,7 @@
 #define SEEN_SP_HATCH_PATH_H
 
 #include <list>
-#include <stddef.h>
+#include <cstddef>
 #include <glibmm/ustring.h>
 #include <sigc++/connection.h>
 
diff --git a/src/object/sp-hatch.h b/src/object/sp-hatch.h
index fc978a74d..f8baf6bfb 100644
--- a/src/object/sp-hatch.h
+++ b/src/object/sp-hatch.h
@@ -16,7 +16,7 @@
 #define SEEN_SP_HATCH_H
 
 #include <list>
-#include <stddef.h>
+#include <cstddef>
 #include <glibmm/ustring.h>
 #include <sigc++/connection.h>
 
diff --git a/src/object/sp-object.h b/src/object/sp-object.h
index 3b083761e..cffa28d2f 100644
--- a/src/object/sp-object.h
+++ b/src/object/sp-object.h
@@ -52,7 +52,7 @@ class SPObject;
 #define SP_OBJECT_WRITE_NO_CHILDREN (1 << 3)
 
 #include <cassert>
-#include <stddef.h>
+#include <cstddef>
 #include <sigc++/connection.h>
 #include <sigc++/functors/slot.h>
 #include <sigc++/signal.h>
diff --git a/src/object/sp-pattern.h b/src/object/sp-pattern.h
index dd590280e..4f37e9a2b 100644
--- a/src/object/sp-pattern.h
+++ b/src/object/sp-pattern.h
@@ -14,7 +14,7 @@
 #define SEEN_SP_PATTERN_H
 
 #include <list>
-#include <stddef.h>
+#include <cstddef>
 #include <glibmm/ustring.h>
 #include <sigc++/connection.h>
 
diff --git a/src/object/sp-tag-use-reference.h b/src/object/sp-tag-use-reference.h
index c7a193d42..50035ab70 100644
--- a/src/object/sp-tag-use-reference.h
+++ b/src/object/sp-tag-use-reference.h
@@ -9,7 +9,7 @@
  * Released under GNU GPL, read the file 'COPYING' for more information.
  */
 
-#include <stddef.h>
+#include <cstddef>
 #include <sigc++/sigc++.h>
 #include <glib.h>
 
diff --git a/src/object/sp-tag-use.h b/src/object/sp-tag-use.h
index 122f11efe..4d354f4ce 100644
--- a/src/object/sp-tag-use.h
+++ b/src/object/sp-tag-use.h
@@ -13,7 +13,7 @@
  */
 
 #include <glib.h>
-#include <stddef.h>
+#include <cstddef>
 #include <sigc++/sigc++.h>
 #include "svg/svg-length.h"
 #include "sp-object.h"
diff --git a/src/selection-describer.h b/src/selection-describer.h
index 60576c6a9..d9da16672 100644
--- a/src/selection-describer.h
+++ b/src/selection-describer.h
@@ -12,7 +12,7 @@
 #ifndef SEEN_INKSCAPE_SELECTION_DESCRIPTION_HANDLER_H
 #define SEEN_INKSCAPE_SELECTION_DESCRIPTION_HANDLER_H
 
-#include <stddef.h>
+#include <cstddef>
 #include <sigc++/sigc++.h>
 #include "message-context.h"
 
diff --git a/src/selection.h b/src/selection.h
index 4fbd0fc39..3ab70265d 100644
--- a/src/selection.h
+++ b/src/selection.h
@@ -17,7 +17,7 @@
 
 #include <vector>
 #include <map>
-#include <stddef.h>
+#include <cstddef>
 #include <sigc++/sigc++.h>
 
 #include "inkgc/gc-managed.h"
diff --git a/src/svg/svg-color.cpp b/src/svg/svg-color.cpp
index 5d8a5c448..32ced67a5 100644
--- a/src/svg/svg-color.cpp
+++ b/src/svg/svg-color.cpp
@@ -19,9 +19,9 @@
 #include <cstdio> // sprintf
 #include <cstring>
 #include <string>
-#include <math.h>
+#include <cmath>
 #include <glib.h> // g_assert
-#include <errno.h>
+#include <cerrno>
 
 #include <map>
 
diff --git a/src/syseq.h b/src/syseq.h
index 6a6ea5055..4b232052c 100644
--- a/src/syseq.h
+++ b/src/syseq.h
@@ -16,7 +16,7 @@
 #include <iostream>
 #include <iomanip>
 #include <vector>
-#include "math.h"
+#include <cmath>
 
 namespace SysEq {
 
diff --git a/src/trace/filterset.cpp b/src/trace/filterset.cpp
index db6d16eea..cfe120324 100644
--- a/src/trace/filterset.cpp
+++ b/src/trace/filterset.cpp
@@ -11,7 +11,7 @@
  */
 
 #include <cstdio>
-#include <stdlib.h>
+#include <cstdlib>
 
 #include "imagemap-gdk.h"
 #include "filterset.h"
diff --git a/src/trace/imagemap-gdk.cpp b/src/trace/imagemap-gdk.cpp
index db8bbdd99..7ce0d3baf 100644
--- a/src/trace/imagemap-gdk.cpp
+++ b/src/trace/imagemap-gdk.cpp
@@ -1,4 +1,4 @@
-#include <stdlib.h>
+#include <cstdlib>
 
 #include "imagemap-gdk.h"
 
diff --git a/src/trace/imagemap.cpp b/src/trace/imagemap.cpp
index e2e97d5ec..1b5b4b791 100644
--- a/src/trace/imagemap.cpp
+++ b/src/trace/imagemap.cpp
@@ -1,4 +1,4 @@
-#include <stdlib.h>
+#include <cstdlib>
 
 #include "imagemap.h"
 
diff --git a/src/trace/pool.h b/src/trace/pool.h
index b4693d941..6ed49b552 100644
--- a/src/trace/pool.h
+++ b/src/trace/pool.h
@@ -51,7 +51,7 @@
 
 */
 
-#include <stdlib.h>
+#include <cstdlib>
 
 template <typename T>
 class pool {
diff --git a/src/trace/potrace/bitmap.h b/src/trace/potrace/bitmap.h
index a47de24d0..679209cf8 100644
--- a/src/trace/potrace/bitmap.h
+++ b/src/trace/potrace/bitmap.h
@@ -5,10 +5,10 @@
 #ifndef BITMAP_H
 #define BITMAP_H
 
-#include <string.h>
-#include <stdlib.h>
-#include <errno.h>
-#include <stddef.h>
+#include <cstring>
+#include <cstdlib>
+#include <cerrno>
+#include <cstddef>
 
 /* The bitmap type is defined in potracelib.h */
 #include "potracelib.h"
diff --git a/src/trace/quantize.cpp b/src/trace/quantize.cpp
index a7868fd03..9601219e2 100644
--- a/src/trace/quantize.cpp
+++ b/src/trace/quantize.cpp
@@ -11,7 +11,7 @@
 
 #include <cassert>
 #include <cstdio>
-#include <stdlib.h>
+#include <cstdlib>
 #include <new>
 
 #include "pool.h"
diff --git a/src/trace/siox.cpp b/src/trace/siox.cpp
index e82f272ab..c04be69fe 100644
--- a/src/trace/siox.cpp
+++ b/src/trace/siox.cpp
@@ -7,8 +7,8 @@
  */
 #include "siox.h"
 
-#include <math.h>
-#include <stdarg.h>
+#include <cmath>
+#include <cstdarg>
 #include <map>
 #include <algorithm>
 #include <cstdlib>
diff --git a/src/trace/trace.h b/src/trace/trace.h
index 10f7c08be..9f680752b 100644
--- a/src/trace/trace.h
+++ b/src/trace/trace.h
@@ -13,7 +13,7 @@
 # include "config.h"
 #endif
 
-# include <string.h>
+# include <cstring>
 
 #include <glibmm/refptr.h>
 #include <gdkmm/pixbuf.h>
diff --git a/src/ui/dialog/color-item.cpp b/src/ui/dialog/color-item.cpp
index 4ebee6834..61709f791 100644
--- a/src/ui/dialog/color-item.cpp
+++ b/src/ui/dialog/color-item.cpp
@@ -15,7 +15,7 @@
 #include "config.h"
 #endif
 
-#include <errno.h>
+#include <cerrno>
 
 #include <gtkmm/label.h>
 #include <glibmm/i18n.h>
diff --git a/src/ui/dialog/document-metadata.h b/src/ui/dialog/document-metadata.h
index fd4f76c88..1696bdb15 100644
--- a/src/ui/dialog/document-metadata.h
+++ b/src/ui/dialog/document-metadata.h
@@ -18,7 +18,7 @@
 #endif
 
 #include <list>
-#include <stddef.h>
+#include <cstddef>
 #include "ui/widget/panel.h"
 #include <gtkmm/notebook.h>
 #include <gtkmm/grid.h>
diff --git a/src/ui/dialog/document-properties.h b/src/ui/dialog/document-properties.h
index 89c87f5de..3607af441 100644
--- a/src/ui/dialog/document-properties.h
+++ b/src/ui/dialog/document-properties.h
@@ -14,7 +14,7 @@
 #ifndef INKSCAPE_UI_DIALOG_DOCUMENT_PREFERENCES_H
 #define INKSCAPE_UI_DIALOG_DOCUMENT_PREFERENCES_H
 
-#include <stddef.h>
+#include <cstddef>
 #include <sigc++/sigc++.h>
 #include <gtkmm/comboboxtext.h>
 #include <gtkmm/liststore.h>
diff --git a/src/ui/dialog/filedialogimpl-gtkmm.h b/src/ui/dialog/filedialogimpl-gtkmm.h
index 771b08df7..6c5cb38e5 100644
--- a/src/ui/dialog/filedialogimpl-gtkmm.h
+++ b/src/ui/dialog/filedialogimpl-gtkmm.h
@@ -26,7 +26,7 @@
 //General includes
 #include <unistd.h>
 #include <sys/stat.h>
-#include <errno.h>
+#include <cerrno>
 
 #include "filedialog.h"
 
diff --git a/src/ui/dialog/inkscape-preferences.h b/src/ui/dialog/inkscape-preferences.h
index 7aaef90b4..3a1105b11 100644
--- a/src/ui/dialog/inkscape-preferences.h
+++ b/src/ui/dialog/inkscape-preferences.h
@@ -23,7 +23,7 @@
 #include <vector>
 #include "ui/widget/preferences-widget.h"
 #include "ui/widget/button.h"
-#include <stddef.h>
+#include <cstddef>
 #include <gtkmm/colorbutton.h>
 #include <gtkmm/comboboxtext.h>
 #include <gtkmm/treestore.h>
diff --git a/src/ui/shape-editor.cpp b/src/ui/shape-editor.cpp
index 4c11a8b52..1c61a2dea 100644
--- a/src/ui/shape-editor.cpp
+++ b/src/ui/shape-editor.cpp
@@ -11,7 +11,7 @@
 #include <config.h>
 #endif
 
-#include <string.h>
+#include <cstring>
 #include <glibmm/i18n.h>
 
 #include "desktop.h"
diff --git a/src/ui/tool/control-point-selection.h b/src/ui/tool/control-point-selection.h
index ca00800c0..192e273e0 100644
--- a/src/ui/tool/control-point-selection.h
+++ b/src/ui/tool/control-point-selection.h
@@ -15,7 +15,7 @@
 #include <list>
 #include <memory>
 #include <boost/optional.hpp>
-#include <stddef.h>
+#include <cstddef>
 #include <sigc++/sigc++.h>
 #include <2geom/forward.h>
 #include <2geom/point.h>
diff --git a/src/ui/tool/control-point.h b/src/ui/tool/control-point.h
index 2ff5b7355..9b71522e3 100644
--- a/src/ui/tool/control-point.h
+++ b/src/ui/tool/control-point.h
@@ -12,7 +12,7 @@
 
 #include <gdkmm/pixbuf.h>
 #include <boost/utility.hpp>
-#include <stddef.h>
+#include <cstddef>
 #include <sigc++/signal.h>
 #include <sigc++/trackable.h>
 #include <2geom/point.h>
diff --git a/src/ui/tool/manipulator.h b/src/ui/tool/manipulator.h
index 25862a039..0e6c1ae4e 100644
--- a/src/ui/tool/manipulator.h
+++ b/src/ui/tool/manipulator.h
@@ -13,7 +13,7 @@
 
 #include <set>
 #include <map>
-#include <stddef.h>
+#include <cstddef>
 #include <sigc++/sigc++.h>
 #include <glib.h>
 #include <gdk/gdk.h>
diff --git a/src/ui/tool/multi-path-manipulator.h b/src/ui/tool/multi-path-manipulator.h
index 46f0d17ba..3e5667591 100644
--- a/src/ui/tool/multi-path-manipulator.h
+++ b/src/ui/tool/multi-path-manipulator.h
@@ -11,7 +11,7 @@
 #ifndef SEEN_UI_TOOL_MULTI_PATH_MANIPULATOR_H
 #define SEEN_UI_TOOL_MULTI_PATH_MANIPULATOR_H
 
-#include <stddef.h>
+#include <cstddef>
 #include <sigc++/connection.h>
 #include "node.h"
 #include "commit-events.h"
diff --git a/src/ui/tool/transform-handle-set.cpp b/src/ui/tool/transform-handle-set.cpp
index 56c34b4d9..de91e10e4 100644
--- a/src/ui/tool/transform-handle-set.cpp
+++ b/src/ui/tool/transform-handle-set.cpp
@@ -9,7 +9,7 @@
  * Released under GNU GPL, read the file 'COPYING' for more information
  */
 
-#include <math.h>
+#include <cmath>
 #include <algorithm>
 
 #include <glib/gi18n.h>
diff --git a/src/ui/tools/arc-tool.h b/src/ui/tools/arc-tool.h
index 7232f07af..2cb2768eb 100644
--- a/src/ui/tools/arc-tool.h
+++ b/src/ui/tools/arc-tool.h
@@ -15,7 +15,7 @@
  * Released under GNU GPL, read the file 'COPYING' for more information
  */
 
-#include <stddef.h>
+#include <cstddef>
 
 #include <2geom/point.h>
 #include <sigc++/connection.h>
diff --git a/src/ui/tools/box3d-tool.h b/src/ui/tools/box3d-tool.h
index cbd7dbe08..513d6d25f 100644
--- a/src/ui/tools/box3d-tool.h
+++ b/src/ui/tools/box3d-tool.h
@@ -15,7 +15,7 @@
  * Released under GNU GPL
  */
 
-#include <stddef.h>
+#include <cstddef>
 
 #include <2geom/point.h>
 #include <sigc++/connection.h>
diff --git a/src/ui/tools/gradient-tool.h b/src/ui/tools/gradient-tool.h
index 3b7a646e7..6421e75ad 100644
--- a/src/ui/tools/gradient-tool.h
+++ b/src/ui/tools/gradient-tool.h
@@ -15,7 +15,7 @@
  * Released under GNU GPL
  */
 
-#include <stddef.h>
+#include <cstddef>
 #include <sigc++/sigc++.h>
 #include "ui/tools/tool-base.h"
 
diff --git a/src/ui/tools/measure-tool.h b/src/ui/tools/measure-tool.h
index e50caa434..f87ac2c81 100644
--- a/src/ui/tools/measure-tool.h
+++ b/src/ui/tools/measure-tool.h
@@ -16,7 +16,7 @@
 # include <config.h>
 #endif
 
-#include <stddef.h>
+#include <cstddef>
 #include <sigc++/sigc++.h>
 #include "ui/tools/tool-base.h"
 #include <2geom/point.h>
diff --git a/src/ui/tools/mesh-tool.h b/src/ui/tools/mesh-tool.h
index 59c60dad4..df3389b9b 100644
--- a/src/ui/tools/mesh-tool.h
+++ b/src/ui/tools/mesh-tool.h
@@ -17,7 +17,7 @@
  * Released under GNU GPL
  */
 
-#include <stddef.h>
+#include <cstddef>
 #include <sigc++/sigc++.h>
 #include "ui/tools/tool-base.h"
 
diff --git a/src/ui/tools/rect-tool.h b/src/ui/tools/rect-tool.h
index 4036bf35b..02760c757 100644
--- a/src/ui/tools/rect-tool.h
+++ b/src/ui/tools/rect-tool.h
@@ -15,7 +15,7 @@
  * Released under GNU GPL
  */
 
-#include <stddef.h>
+#include <cstddef>
 #include <sigc++/sigc++.h>
 #include <2geom/point.h>
 #include "ui/tools/tool-base.h"
diff --git a/src/ui/tools/star-tool.h b/src/ui/tools/star-tool.h
index 2e973fad5..6d448bf7f 100644
--- a/src/ui/tools/star-tool.h
+++ b/src/ui/tools/star-tool.h
@@ -14,7 +14,7 @@
  * Released under GNU GPL, read the file 'COPYING' for more information
  */
 
-#include <stddef.h>
+#include <cstddef>
 #include <sigc++/sigc++.h>
 #include <2geom/point.h>
 #include "ui/tools/tool-base.h"
diff --git a/src/ui/tools/tool-base.h b/src/ui/tools/tool-base.h
index 1696c6453..2d743ec67 100644
--- a/src/ui/tools/tool-base.h
+++ b/src/ui/tools/tool-base.h
@@ -12,7 +12,7 @@
  * Released under GNU GPL, read the file 'COPYING' for more information
  */
 
-#include <stddef.h>
+#include <cstddef>
 #include <string>
 #include "knot.h"
 #include "knotholder.h"
diff --git a/src/ui/view/view.h b/src/ui/view/view.h
index 200b52e7a..532bf36a8 100644
--- a/src/ui/view/view.h
+++ b/src/ui/view/view.h
@@ -12,7 +12,7 @@
  */
 
 #include <gdk/gdk.h>
-#include <stddef.h>
+#include <cstddef>
 #include <sigc++/connection.h>
 #include "message.h"
 #include "inkgc/gc-managed.h"
diff --git a/src/ui/widget/color-picker.h b/src/ui/widget/color-picker.h
index c80571df0..325ba7d13 100644
--- a/src/ui/widget/color-picker.h
+++ b/src/ui/widget/color-picker.h
@@ -15,7 +15,7 @@
 
 #include "labelled.h"
 
-#include <stddef.h>
+#include <cstddef>
 
 #include <gtkmm/dialog.h>
 #include <gtkmm/button.h>
diff --git a/src/ui/widget/page-sizer.h b/src/ui/widget/page-sizer.h
index edc9f5b0c..d64034b8c 100644
--- a/src/ui/widget/page-sizer.h
+++ b/src/ui/widget/page-sizer.h
@@ -14,7 +14,7 @@
 # include <config.h>
 #endif
 
-#include <stddef.h>
+#include <cstddef>
 #include "ui/widget/registered-widget.h"
 #include <sigc++/sigc++.h>
 
diff --git a/src/ui/widget/preferences-widget.h b/src/ui/widget/preferences-widget.h
index acd59fe94..8e1602ff9 100644
--- a/src/ui/widget/preferences-widget.h
+++ b/src/ui/widget/preferences-widget.h
@@ -24,7 +24,7 @@
 
 #include <gtkmm/filechooserbutton.h>
 #include "ui/widget/spinbutton.h"
-#include <stddef.h>
+#include <cstddef>
 #include <sigc++/sigc++.h>
 #include <gtkmm/checkbutton.h>
 #include <gtkmm/radiobutton.h>
diff --git a/src/ui/widget/selected-style.h b/src/ui/widget/selected-style.h
index 6f1841928..1437624fa 100644
--- a/src/ui/widget/selected-style.h
+++ b/src/ui/widget/selected-style.h
@@ -28,7 +28,7 @@
 #include <gtkmm/radiomenuitem.h>
 #include "ui/widget/spinbutton.h"
 
-#include <stddef.h>
+#include <cstddef>
 #include <sigc++/sigc++.h>
 
 #include "rotateable.h"
diff --git a/src/ui/widget/style-subject.h b/src/ui/widget/style-subject.h
index 398aab065..3a3010f46 100644
--- a/src/ui/widget/style-subject.h
+++ b/src/ui/widget/style-subject.h
@@ -12,7 +12,7 @@
 
 #include <boost/optional.hpp>
 #include <2geom/rect.h>
-#include <stddef.h>
+#include <cstddef>
 #include <sigc++/sigc++.h>
 
 #include "object/sp-item.h"
diff --git a/src/unicoderange.cpp b/src/unicoderange.cpp
index 2adb26311..7930fb4a7 100644
--- a/src/unicoderange.cpp
+++ b/src/unicoderange.cpp
@@ -1,7 +1,7 @@
 #include "unicoderange.h"
 
-#include <stdlib.h>
-#include <string.h>
+#include <cstdlib>
+#include <cstring>
 
 static unsigned int hex2int(char* s){
     int res=0;
diff --git a/src/util/expression-evaluator.cpp b/src/util/expression-evaluator.cpp
index 47c54a995..2c719100c 100644
--- a/src/util/expression-evaluator.cpp
+++ b/src/util/expression-evaluator.cpp
@@ -30,8 +30,8 @@
 
 #include <glib/gconvert.h>
 
-#include <math.h>
-#include <string.h>
+#include <cmath>
+#include <cstring>
 
 using Inkscape::Util::unit_table;
 
diff --git a/src/util/fixed_point.h b/src/util/fixed_point.h
index 02d536ecc..f2bf0318d 100644
--- a/src/util/fixed_point.h
+++ b/src/util/fixed_point.h
@@ -13,7 +13,7 @@
 #define SEEN_INKSCAPE_UTIL_FIXED_POINT_H
 
 #include "util/reference.h"
-#include <math.h>
+#include <cmath>
 #include <algorithm>
 #include <limits>
 
diff --git a/src/util/format.h b/src/util/format.h
index d2fe2d0ef..61e004857 100644
--- a/src/util/format.h
+++ b/src/util/format.h
@@ -12,7 +12,7 @@
 #ifndef SEEN_INKSCAPE_UTIL_FORMAT_H
 #define SEEN_INKSCAPE_UTIL_FORMAT_H
 
-#include <stdarg.h>
+#include <cstdarg>
 #include <glib.h>
 #include "util/share.h"
 
diff --git a/src/util/ziptool.cpp b/src/util/ziptool.cpp
index 2146710dd..fe64bad6f 100644
--- a/src/util/ziptool.cpp
+++ b/src/util/ziptool.cpp
@@ -31,9 +31,9 @@
  */
 
 
-#include <stdio.h>
-#include <stdarg.h>
-#include <time.h>
+#include <cstdio>
+#include <cstdarg>
+#include <ctime>
 
 #include <string>
 
diff --git a/src/widgets/desktop-widget.h b/src/widgets/desktop-widget.h
index 4744752dc..60b100028 100644
--- a/src/widgets/desktop-widget.h
+++ b/src/widgets/desktop-widget.h
@@ -17,7 +17,7 @@
 #include "ui/view/view-widget.h"
 #include "ui/view/edit-widget-interface.h"
 
-#include <stddef.h>
+#include <cstddef>
 #include <sigc++/connection.h>
 #include <2geom/point.h>
 
diff --git a/src/widgets/ege-adjustment-action.cpp b/src/widgets/ege-adjustment-action.cpp
index ba120c310..5b71110b2 100644
--- a/src/widgets/ege-adjustment-action.cpp
+++ b/src/widgets/ege-adjustment-action.cpp
@@ -40,7 +40,7 @@
 /* Note: this file should be kept compilable as both .cpp and .c */
 
 #include <cmath>
-#include <string.h>
+#include <cstring>
 #include <vector>
 #include <algorithm>
 
diff --git a/src/widgets/ege-output-action.cpp b/src/widgets/ege-output-action.cpp
index 847a4f0a1..929e8e5ea 100644
--- a/src/widgets/ege-output-action.cpp
+++ b/src/widgets/ege-output-action.cpp
@@ -39,7 +39,7 @@
 
 /* Note: this file should be kept compilable as both .cpp and .c */
 
-#include <string.h>
+#include <cstring>
 
 #include <gtk/gtk.h>
 #include <gtkmm/container.h>
diff --git a/src/widgets/ege-paint-def.cpp b/src/widgets/ege-paint-def.cpp
index aa51cf33a..8ed6bbfc5 100644
--- a/src/widgets/ege-paint-def.cpp
+++ b/src/widgets/ege-paint-def.cpp
@@ -38,12 +38,12 @@
 
 #include <libintl.h>
 
-#include <stdint.h>
+#include <cstdint>
 #include <string>
 #include <iostream>
 #include <sstream>
-#include <string.h>
-#include <stdio.h>
+#include <cstring>
+#include <cstdio>
 #include <glibmm/i18n.h>
 #include <glibmm/stringutils.h>
 
diff --git a/src/widgets/ink-comboboxentry-action.cpp b/src/widgets/ink-comboboxentry-action.cpp
index 5aace3f34..65f7d5831 100644
--- a/src/widgets/ink-comboboxentry-action.cpp
+++ b/src/widgets/ink-comboboxentry-action.cpp
@@ -24,7 +24,7 @@
  */
 
 #include <iostream>
-#include <string.h>
+#include <cstring>
 #include <glibmm/ustring.h>
 
 #include <gtk/gtk.h>
diff --git a/src/widgets/sp-attribute-widget.h b/src/widgets/sp-attribute-widget.h
index de1b95e9c..7aad9bdc7 100644
--- a/src/widgets/sp-attribute-widget.h
+++ b/src/widgets/sp-attribute-widget.h
@@ -20,7 +20,7 @@
 #endif
 
 #include <gtkmm/widget.h>
-#include <stddef.h>
+#include <cstddef>
 #include <sigc++/connection.h>
 
 namespace Gtk {
diff --git a/src/widgets/sp-color-selector.cpp b/src/widgets/sp-color-selector.cpp
index 87051352f..f4931e5e9 100644
--- a/src/widgets/sp-color-selector.cpp
+++ b/src/widgets/sp-color-selector.cpp
@@ -7,7 +7,7 @@
 #include <config.h>
 #endif
 
-#include <math.h>
+#include <cmath>
 #include <gtk/gtk.h>
 #include <glibmm/i18n.h>
 #include "sp-color-selector.h"