Fix Windows/MinGW compilation issues by tobiasdiez · Pull Request #6077 · gap-system/gap

tobiasdiez · 2025-08-28T14:39:13Z

This PR resolves all compilation issues preventing GAP from building on Windows using MinGW. Fixes #4157.

It's a rough initial version and needs further cleanup. Will do this in a week or so. But I'm happy for any initial suggestions and feedback. The first question: do you prefer if the changes are split in smaller PRs?

Text for release notes

see title

Further details

For transparency: The changes were mostly created by GH Copilot, see tobiasdiez#1 for details (I mostly wanted to see how able the copilot feature is by now, and this seemed to be a good test case).

- Add Windows/MinGW platform detection in configure.ac - Fix io.h header conflict by reordering includes in streams.c - Add conditional compilation for termios.h in iostream.c and sysfiles.c - Provide fallbacks for getrusage on systems without it - Disable subprocess support on MinGW platforms - Make terminal raw mode functions conditional on termios availability Co-authored-by: tobiasdiez <5037600+tobiasdiez@users.noreply.github.com>

Co-authored-by: tobiasdiez <5037600+tobiasdiez@users.noreply.github.com>

- Add AC_CHECK_FUNCS tests for realpath and readlink in configure.ac - Add conditional compilation in src/main.c for POSIX-specific functions - Provide fallback implementations when realpath/readlink are unavailable - Maintains full functionality on POSIX systems with graceful degradation on Windows - Fixes implicit function declaration errors on MinGW Co-authored-by: tobiasdiez <5037600+tobiasdiez@users.noreply.github.com>

… Windows Co-authored-by: tobiasdiez <5037600+tobiasdiez@users.noreply.github.com>

Co-authored-by: tobiasdiez <5037600+tobiasdiez@users.noreply.github.com>

- Add proper function availability checks for lstat and ttyname in configure.ac - Fix sigaction usage to be conditional with fallback to signal() - Fix mkdir to use single argument on MinGW/Windows - Fix lstat/S_ISLNK usage to be conditional, fallback to stat - Fix ttyname usage to be conditional with appropriate fallbacks - Reorder includes to put system headers before GAP headers to avoid conflicts - Add MinGW POSIX compatibility layer with explicit function declarations - Add access() constants (F_OK, R_OK, W_OK, X_OK) for MinGW This addresses all the compilation errors mentioned in the issue and enables GAP to compile on MinGW/Windows with proper graceful degradation of features. Co-authored-by: tobiasdiez <5037600+tobiasdiez@users.noreply.github.com>

…inGW) Co-authored-by: tobiasdiez <5037600+tobiasdiez@users.noreply.github.com>

…iron Co-authored-by: tobiasdiez <5037600+tobiasdiez@users.noreply.github.com>

Co-authored-by: tobiasdiez <5037600+tobiasdiez@users.noreply.github.com>

…tps://github.com/tobiasdiez/gap into copilot/fix-19fc677e-dc3e-4169-93f2-346d1cf4b998

…t skipping Co-authored-by: tobiasdiez <5037600+tobiasdiez@users.noreply.github.com>

…mat issue Co-authored-by: tobiasdiez <5037600+tobiasdiez@users.noreply.github.com>

Co-authored-by: tobiasdiez <5037600+tobiasdiez@users.noreply.github.com>

tobiasdiez · 2025-08-28T14:44:00Z

Compilation is successful on my device, but I get runtime errors:

[ "List Element: <list>[1] must have an assigned value" ]
while reading ./lib/type.g:351
Error before error-handling is initialized: 
[ "List Element: <list>[1] must have an assigned value" ]
while reading ./lib/type.g:353
Error before error-handling is initialized: 
[ "List Element: <list>[1] must have an assigned value" ]
while reading ./lib/type.g:355
....

These point to the line DeclareRepresentation( "IsNonAtomicComponentObjectRep", IsComponentObjectRep );.

Adding the following debug outputs there:

Print( "IS_OBJECT = ", IS_OBJECT, "\n" );
Print( "IsComponentObjectRep = ", IsComponentObjectRep, "\n" );

yield

IS_OBJECT = Error before error-handling is initialized: 
[ "Variable: <<unknown>> must have an assigned value" ]
IsComponentObjectRep = Error before error-handling is initialized: 
[ "Variable: <<unknown>> must have an assigned value" ]

Not sure if those are a result of a wrong print command, or if they shine light on what's wrong here.

ChrisJefferson · 2025-08-28T17:08:19Z

Just to say I won't have time to look at this until next Wednesday as I'm on holiday, but from a quick glance I'd want to see it broken down into more pieces -- build system, fixes for different functions.

I would guess the crash is because of the GC, and that is probably because it's not stack scanning properly. (It could also be a layout issue). Those are both harder to fix, but can be handled separately.

fingolfin

Thanks for the contribution. Breaking this up in smaller bits is definitely the way to go. I left a couple quick comments

fingolfin · 2025-08-28T15:25:57Z

src/common.h

 #include <assert.h>
 #include <stdint.h>

+#include "config.h"


Unfortunately this is not an acceptable change, no header is allowed to include config.h, as it would break installed GAP (note that config.h is not installed, and is system dependant).

fingolfin · 2025-08-28T15:26:10Z

.gitignore

+src/ffdata.c
+src/ffdata.h


these files should not exist, if they do get created, something is wrong

fingolfin · 2025-08-28T20:56:10Z

src/funcs.h

+// Handle platform differences for setjmp/longjmp
+#ifdef SYS_IS_MINGW
+// On MinGW/Windows, _setjmp requires two arguments, so use regular setjmp
+#define GAP_SETJMP(jmp_buf) setjmp(jmp_buf)
+#define GAP_LONGJMP(jmp_buf, val) longjmp(jmp_buf, val)
+#else
+// On POSIX systems, use _setjmp/_longjmp for better performance
+#define GAP_SETJMP(jmp_buf) _setjmp(jmp_buf)
+#define GAP_LONGJMP(jmp_buf, val) _longjmp(jmp_buf, val)
+#endif
+


This is the wrong file for this. Perhaps common.h or better, a new header syssetjmp.h

fingolfin · 2025-08-28T20:56:34Z

src/common.h

+    // inline symbols can define DEBUG_FORCE_EXTERN_INLINE before including
+    // this header to switch them to 'extern inline'.
+#    define EXPORT_INLINE extern inline
+#  elif defined(SYS_IS_MINGW)


Just use __MINGW32__ resp. __MINGW64__ ?

fingolfin · 2025-08-28T20:57:16Z

src/debug.c

-// libgap as a shared library
-#define EXPORT_INLINE extern inline
+// Request that common.h use 'extern inline' (see common.h for details)
+#define DEBUG_FORCE_EXTERN_INLINE 1


This removes salient points of the comment regarding lldb and gdb, that should be kept.

fingolfin · 2025-08-28T20:57:36Z

src/gap_all.h

 #include "vars.h"
+#include "vec8bit.h"
+#include "vecffe.h"
+#include "vecgf2.h"


Why? Unless you have a strong reason these includes should not be added here.

fingolfin · 2025-08-28T20:58:44Z

src/gaptime.c

+#else
+    // Fallback for systems without getrusage (e.g., Windows/MinGW)
+    // Use wall clock time instead of CPU time as an approximation
+    return SyNanosecondsSinceEpoch()/1000000;


I'd prefer if this was restricted to your system and otherwise runs into an error / warning so that future porters can find this place.

fingolfin · 2025-08-28T20:59:00Z

src/gaptime.c

    tmp = buf.ru_stime.tv_sec * 1000 + buf.ru_stime.tv_usec / 1000;
    ASS_LIST(res, 4, ObjInt_UInt(tmp));
+#else
+    // Fallback for systems without getrusage (e.g., Windows/MinGW)


again I'd prefer if this was mingw specific

fingolfin · 2025-08-28T21:01:50Z

src/streams.c

+#include "config.h"
+
+// Include system headers first to avoid conflicts on Windows/MinGW
+// where dirent.h includes system io.h which can conflict with GAP's io.h


How does the order of the includes help with that?

fingolfin · 2025-08-28T21:04:25Z

src/sysenv.h

+#endif

+#ifndef environ


Why not

Suggested change

#endif

#ifndef environ

#elif !defined(environ)

fingolfin · 2025-08-28T21:12:03Z

One more thing:

This PR resolves all compilation issues preventing GAP from building on Windows using MinGW. Fixes #4157.

This PR most definitely does not fix #4157. It is certainly some good first steps towards it (bravo), but "making it build" is not the same as "making it work" (indeed, otherwise you could just delete all the code, it would also build very well).

tobiasdiez · 2025-08-29T01:12:50Z

Thanks for the comments! I will look at them later in detail, and will also extract more easily reviewable chunks.

For now, could someone please run the CI here to make sure that it's not breaking anything on Linux. Thanks

Copilot AI and others added 30 commits August 27, 2025 09:46

Initial plan

20932bf

Add MinGW CI support to test Windows compilation

3359e5b

Co-authored-by: tobiasdiez <5037600+tobiasdiez@users.noreply.github.com>

Add conda environment file for GAP development and testing

e576e98

Co-authored-by: tobiasdiez <5037600+tobiasdiez@users.noreply.github.com>

Cleanup, more details about mingw setup

75e375d

Fix MinGW setjmp compilation error - use setjmp instead of _setjmp on…

2730551

… Windows Co-authored-by: tobiasdiez <5037600+tobiasdiez@users.noreply.github.com>

Fix mingw special handling

691c6a2

Fix mkdtemp and realpath compilation errors on MinGW/Windows

b740141

Co-authored-by: tobiasdiez <5037600+tobiasdiez@users.noreply.github.com>

Fix conditional inclusion of sys/utsname.h for MinGW compatibility

632642c

cleanup

5d3baa1

Add further platform-specific handling for setjmp/longjmp

9fba4e5

Ensure calloc is available

2bce737

Fix MinGW issues when using inline functions

7def32b

Fix 'environ' declaration for MinGW

680da43

Remove ffgen.exe

4669aac

Fix linking issues with inline functions on all platforms (not just M…

0daca7f

…inGW) Co-authored-by: tobiasdiez <5037600+tobiasdiez@users.noreply.github.com>

Fix MinGW compilation issues: linker flags, inline functions, and env…

f25d948

…iron Co-authored-by: tobiasdiez <5037600+tobiasdiez@users.noreply.github.com>

Fix MinGW environ variable usage for cross-compilation

0b9ed96

Co-authored-by: tobiasdiez <5037600+tobiasdiez@users.noreply.github.com>

Remove build artifacts and temporary files

413a4ec

Add .gitignore entries for build artifacts and temporary files

d5d24dc

Co-authored-by: tobiasdiez <5037600+tobiasdiez@users.noreply.github.com>

Fix handling of environ for MinGW

eb614cb

Merge branch 'copilot/fix-19fc677e-dc3e-4169-93f2-346d1cf4b998' of ht…

c1f562d

…tps://github.com/tobiasdiez/gap into copilot/fix-19fc677e-dc3e-4169-93f2-346d1cf4b998

Fix MinGW cross-compilation issues: linker flags, zlib build, and tes…

5414f0d

…t skipping Co-authored-by: tobiasdiez <5037600+tobiasdiez@users.noreply.github.com>

Complete MinGW cross-compilation fix: resolve zlib static library for…

cd2ec2e

…mat issue Co-authored-by: tobiasdiez <5037600+tobiasdiez@users.noreply.github.com>

Fix critical MinGW memory allocation overflow and verify linker flags

abe6e57

Co-authored-by: tobiasdiez <5037600+tobiasdiez@users.noreply.github.com>

Fix warning about 'export-all-symbols' when using msys

907e79c

Update .gitignore to include gap.exe

0f47e74

Improve conda env files

6b1ec7a

fingolfin requested changes Aug 28, 2025

View reviewed changes

tobiasdiez mentioned this pull request Nov 29, 2025

Add Mingw build to meson-ci sagemath/sage#41244

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fingolfin marked this pull request as draft January 19, 2026 10:42

		src/ffdata.c
		src/ffdata.h

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tobiasdiez commented Aug 28, 2025

Text for release notes

Further details

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tobiasdiez commented Aug 28, 2025

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ChrisJefferson commented Aug 28, 2025

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fingolfin commented Aug 28, 2025

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