Tk fails to compile after gcc upgrade from gcc-12 to gcc-14

[jkeenan]

A Debian upgrade on my Linux server entailed an upgrade in the default version of gcc on this machine. As an apparent consequence, when I test Tk against development releases of Perl, compilation now fails during make, even though there has been no change within Tk and even when compiling with the same version of Perl.

I first became aware of this when comparing CPANtesters reports for Tk run against perl-5.43.9 and, the following month, perl-5.43.10. In between these two runs, I upgraded from Debian 12 (bookworm) to Debian 13 (trixie).

https://www.cpantesters.org/cpan/report/a0602756-247e-11f1-94b3-e8d499459050

Date: 2026-03-20
Perl version: 5.43.9
Grade: PASS (though no tests were run)
osname=linux
osvers=6.1.0-37-amd64
archname=x86_64-linux
uname='linux jk-bookworm 6.1.0-37-amd64 #1 smp preempt_dynamic debian 6.1.140-1 (2025-05-22) x86_64 gnulinux '
config_args='-des -Dusedevel -Dprefix=/home/jkeenan/testing/perl-5.43.9 -Uversiononly -Dman1dir=none -Dman3dir=none'
gccversion='12.2.0'

Date: 2026-04-20
Perl version: 5.43.10
Grade: UNKNOWN (see below)
osname=linux
osvers=6.12.74+deb13+1-amd64
archname=x86_64-linux
uname='linux jk-trixie 6.12.74+deb13+1-amd64 #1 smp preempt_dynamic debian 6.12.74-2 (2026-03-08) x86_64 gnulinux '
config_args='-des -Dusedevel -Dprefix=/home/jkeenan/testing/perl-5.43.10 -Uversiononly -Dman1dir=none -Dman3dir=none'
gccversion='14.2.0'

tail of make failure:

In file included from Xlib_f.c:17:
Xlib.t:334:1: warning: �XKeycodeToKeysym� is deprecated [-Wdeprecated-declarations]
  334 | VFUNC(KeySym,XKeycodeToKeysym,V_XKeycodeToKeysym,_ANSI_ARGS_((Display *, unsigned int, int)))
      | ^~~~~
In file included from Xlib_f.c:4:
/usr/include/X11/Xlib.h:1683:15: note: declared here
 1683 | extern KeySym XKeycodeToKeysym(
      |               ^~~~~~~~~~~~~~~~
Xlib.t:334:14: error: initialization of �KeySym (*)(Display *, unsigned int,  int)� {aka �long unsigned int (*)(Display *, unsigned int,  int)�} from incompatible pointer type �KeySym (*)(Display *, KeyCode,  int)� {aka �long unsigned int (*)(Display *, unsigned char,  int)�} [-Wincompatible-pointer-types]
  334 | VFUNC(KeySym,XKeycodeToKeysym,V_XKeycodeToKeysym,_ANSI_ARGS_((Display *, unsigned int, int)))
      |              ^~~~~~~~~~~~~~~~
Xlib_f.c:15:35: note: in definition of macro �VFUNC�
   15 | #define VFUNC(type,name,mem,args) name,
      |                                   ^~~~
Xlib.t:334:14: note: (near initialization for �XlibVtable.V_XKeycodeToKeysym�)
  334 | VFUNC(KeySym,XKeycodeToKeysym,V_XKeycodeToKeysym,_ANSI_ARGS_((Display *, unsigned int, int)))
      |              ^~~~~~~~~~~~~~~~
Xlib_f.c:15:35: note: in definition of macro �VFUNC�
   15 | #define VFUNC(type,name,mem,args) name,
      |                                   ^~~~
make[1]: *** [Makefile:868: Xlib_f.o] Error 1
make[1]: Leaving directory '/home/jkeenan/.cpan/build/Tk-804.036-0/pTk'
make: *** [Makefile:1661: pTk/libpTk.a] Error 2

In subsequent months Tk has continued to fail during make. See, for example, this report run yesterday (June 22) against perl-5.44.0-RC1: https://www.cpantesters.org/cpan/report/55e25e2c-6ec2-11f1-9659-e31fbcd3a85a

I wanted to rule out the possibility that this failure was due to a change in Perl itself between 5.43.9 and 5.43.10. So yesterday I re-downloaded the 5.43.9 tarball and installed it in a distinct directory, then attempted to install Tk against it (without trying to generate a CPANtesters report). Of course now there are deeper changes on the machine: Debian 13 and gcc-14. Tk failed during make like this:

cc -c  -I..  -I. -Ibitmaps  -fwrapv -fno-strict-aliasing -pipe -fstack-protector-strong -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -D_FORTIFY_SOURCE=2 -O2   -DVERSION=\"804.036\" -DXS_VERSION=\"804.036\" -fPIC "-I/home/jkeenan/testing/alt/perl-5.43.9/lib/5.43.9/x86_64-linux/CORE"    Xlib_f.c
In file included from Xlib_f.c:17:
Xlib.t:334:1: warning: ‘XKeycodeToKeysym’ is deprecated [-Wdeprecated-declarations]
  334 | VFUNC(KeySym,XKeycodeToKeysym,V_XKeycodeToKeysym,_ANSI_ARGS_((Display *, unsigned int, int)))
      | ^~~~~
In file included from Xlib_f.c:4:
/usr/include/X11/Xlib.h:1683:15: note: declared here
 1683 | extern KeySym XKeycodeToKeysym(
      |               ^~~~~~~~~~~~~~~~
Xlib.t:334:14: error: initialization of ‘KeySym (*)(Display *, unsigned int,  int)’ {aka ‘long unsigned int (*)(Display *, unsigned int,  int)’} from incompatible pointer type ‘KeySym (*)(Display *, KeyCode,  int)’ {aka ‘long unsigned int (*)(Display *, unsigned char,  int)’} [-Wincompatible-pointer-types]
  334 | VFUNC(KeySym,XKeycodeToKeysym,V_XKeycodeToKeysym,_ANSI_ARGS_((Display *, unsigned int, int)))
      |              ^~~~~~~~~~~~~~~~
Xlib_f.c:15:35: note: in definition of macro ‘VFUNC’
   15 | #define VFUNC(type,name,mem,args) name,
      |                                   ^~~~
Xlib.t:334:14: note: (near initialization for ‘XlibVtable.V_XKeycodeToKeysym’)
  334 | VFUNC(KeySym,XKeycodeToKeysym,V_XKeycodeToKeysym,_ANSI_ARGS_((Display *, unsigned int, int)))
      |              ^~~~~~~~~~~~~~~~
Xlib_f.c:15:35: note: in definition of macro ‘VFUNC’
   15 | #define VFUNC(type,name,mem,args) name,
      |                                   ^~~~
make[1]: *** [Makefile:868: Xlib_f.o] Error 1
make[1]: Leaving directory '/home/jkeenan/.cpan/build/Tk-804.036-2/pTk'
make: *** [Makefile:1661: pTk/libpTk.a] Error 2
  SREZIC/Tk-804.036.tar.gz
  /usr/bin/make -- NOT OK

So I infer that Tk needs to be upgraded to compile with gcc-14.

Possibly similar tickets:

• 804.036 + master (f0bb386b): build fails #98
• fails with gcc14 #105
• An incompatible-pointer-types in pTk/Xlib.t that induces an error with gcc 14 #106
• fails with gcc15 #112

[jkeenan]

On the same Debian 13 machine as above, today I installed perl-5.44.0-RC1 (from tag rather than tarball) but built with clang-19 instead of the machine's default gcc-14. I then attempted to install Tk against that perl. Tk threw some build-time warnings and then died relatively early during make.

$ uname -mrs
Linux 6.12.74+deb13+1-amd64 x86_64

$ clang --version
Debian clang version 19.1.7 (3+b1)
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/lib/llvm-19/bin

$ ./bin/perl -Ilib -V:config_args
config_args='-des -Dusedevel -Dcc=clang-19 -Dprefix=/home/jkeenan/testing/alt/v5.44.0-RC1 -Uversiononly -Dman1dir=none -Dman3dir=none';

$ make
...
clang-19 -c  -I..  -I. -Ibitmaps  -fno-strict-aliasing -pipe -fstack-protector-strong -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -O2   -DVERSION=\"804.036\" -DXS_VERSION=\"804.036\" -fPIC "-I/home/jkeenan/testing/alt/v5.44.0-RC1/lib/perl5/5.44.0/x86_64-linux/CORE"   -Wall -Wno-implicit-int -Wno-comment -Wno-unused -D__USE_FIXED_PROTOTYPES__ ClientWin.c
ClientWin.c:58:22: warning: passing arguments to 'TryChildren' without a prototype is deprecated in all versions of C and is not supported in C23 [-Wdeprecated-non-prototype]
   58 |     inf = TryChildren(dpy, win, WM_STATE);
      |                      ^
ClientWin.c:37:8: warning: a function definition without a prototype is deprecated in all versions of C and is not supported in C23 [-Wdeprecated-non-prototype]
   37 | Window XmuClientWindow (dpy, win)
      |        ^
ClientWin.c:66:8: warning: a function definition without a prototype is deprecated in all versions of C and is not supported in C23 [-Wdeprecated-non-prototype]
   66 | Window TryChildren (dpy, win, WM_STATE)
      |        ^
ClientWin.c:33:15: warning: a function declaration without a prototype is deprecated in all versions of C and is treated as a zero-parameter prototype in C23, conflicting with a subsequent definition [-Wdeprecated-non-prototype]
   33 | static Window TryChildren();
      |               ^
4 warnings generated.
clang-19 -c  -I..  -I. -Ibitmaps  -fno-strict-aliasing -pipe -fstack-protector-strong -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -O2   -DVERSION=\"804.036\" -DXS_VERSION=\"804.036\" -fPIC "-I/home/jkeenan/testing/alt/v5.44.0-RC1/lib/perl5/5.44.0/x86_64-linux/CORE"   -Wall -Wno-implicit-int -Wno-comment -Wno-unused -D__USE_FIXED_PROTOTYPES__ Lang_f.c
clang-19 -c  -I..  -I. -Ibitmaps  -fno-strict-aliasing -pipe -fstack-protector-strong -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -O2   -DVERSION=\"804.036\" -DXS_VERSION=\"804.036\" -fPIC "-I/home/jkeenan/testing/alt/v5.44.0-RC1/lib/perl5/5.44.0/x86_64-linux/CORE"   -Wall -Wno-implicit-int -Wno-comment -Wno-unused -D__USE_FIXED_PROTOTYPES__ Xlib_f.c
In file included from Xlib_f.c:17:
./Xlib.t:334:14: error: incompatible function pointer types initializing 'KeySym (*)(Display *, unsigned int, int)' (aka 'unsigned long (*)(struct _XDisplay *, unsigned int, int)') with an expression of type 'KeySym (Display *, KeyCode, int)' (aka 'unsigned long (struct _XDisplay *, unsigned char, int)') [-Wincompatible-function-pointer-types]
  334 | VFUNC(KeySym,XKeycodeToKeysym,V_XKeycodeToKeysym,_ANSI_ARGS_((Display *, unsigned int, int)))
      |              ^~~~~~~~~~~~~~~~
Xlib_f.c:15:35: note: expanded from macro 'VFUNC'
   15 | #define VFUNC(type,name,mem,args) name,
      |                                   ^~~~
In file included from Xlib_f.c:17:
./Xlib.t:334:14: warning: 'XKeycodeToKeysym' is deprecated [-Wdeprecated-declarations]
/usr/include/X11/Xlib.h:1682:1: note: 'XKeycodeToKeysym' has been explicitly marked deprecated here
 1682 | _X_DEPRECATED
      | ^
/usr/include/X11/Xfuncproto.h:136:40: note: expanded from macro '_X_DEPRECATED'
  136 | # define _X_DEPRECATED  __attribute__((deprecated))
      |                                        ^
1 warning and 1 error generated.
make[1]: *** [Makefile:868: Xlib_f.o] Error 1
make[1]: Leaving directory '/home/jkeenan/.cpan/build/Tk-804.036-3/pTk'
make: *** [Makefile:1661: pTk/libpTk.a] Error 2
  SREZIC/Tk-804.036.tar.gz
  /usr/bin/make -- NOT OK