Baffling compilation errors from Strawberry Perl

no longer just digit has asked for the wisdom of the Perl Monks concerning the following question:

I'm getting quite baffling compilation errors from Strawberry Perl as seen here.

The errors look like this:

In file included from Libdeflate.xs:3:
C:\STRAWB~1\perl\lib\CORE/XSUB.h:615:21: error: 'PerlMem_malloc' undec
+lared here (not in a function); did you mean 'Perl_malloc'?
 #    define malloc  PerlMem_malloc
                     ^~~~~~~~~~~~~~
C:\STRAWB~1\perl\lib\CORE/XSUB.h:615:21: note: in definition of macro 
+'malloc'
 #    define malloc  PerlMem_malloc
                     ^~~~~~~~~~~~~~
C:\STRAWB~1\perl\lib\CORE/XSUB.h:618:19: error: 'PerlMem_free' undecla
+red here (not in a function); did you mean 'Perl_sv_free'?
 #    define free  PerlMem_free
                   ^~~~~~~~~~~~
C:\STRAWB~1\perl\lib\CORE/XSUB.h:618:19: note: in definition of macro 
+'free'
 #    define free  PerlMem_free
                   ^~~~~~~~~~~~
gmake: *** [Makefile:340: Libdeflate.o] Error 1
-> FAIL Installing Gzip-Libdeflate-0.01_01.tar.gz failed. See C:\Users
+\ben\.cpanm\work\1613793219.7300\build.log for details. Retry with --
+force to force install it.
[download]

On my Perl XSUB.h defines free as above, but I don't understand what this error even means, since it is coming from a #define line where what is on the right shouldn't matter.

I've tried everything I can think of to work out what is happening, but I'm completely stumped.

Comment on Baffling compilation errors from Strawberry Perl Download Code

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Re: Baffling compilation errors from Strawberry Perl by syphilis (Archbishop) on Feb 20, 2021 at 06:19 UTC
Hi, This patch works for me: `--- libdeflate-one.c_orig 2021-02-20 17:12:44 +1100 +++ libdeflate-one.c 2021-02-20 17:23:26 +1100 @@ -27,6 +27,10 @@ /* #include "lib_common.h" / +#ifdef WIN32 +#undef malloc +#undef free +#endif #ifndef LIB_LIB_COMMON_H #define LIB_LIB_COMMON_H` [download] This issue with free/malloc on Windows is not unique to Gzip::Libdeflate. Update: Added "#ifdef WIN32" to provide portability. 'Nother Update: On my Perl XSUB.h defines free as above, but I don't understand what this error even means, since it is coming from a #define line where what is on the right shouldn't matter.* Aaah ... but it does matter in libdeflate-one.c, where `free` (and `malloc`) need to be implemented according to the stdlib.h specification, not according to perl's (re)definition of them. By undef'ing those 2 symbols, we ensure that the stdlib.h implementations are used. Cheers, Rob	[reply] [d/l] [select]
Re^2: Baffling compilation errors from Strawberry Perl by no longer just digit (Beadle) on Feb 21, 2021 at 00:04 UTC
That seems to work. Aaah ... but it does matter in libdeflate-one.c, where free (and malloc) need to be implemented according to the stdlib.h specification, not according to perl's (re)definition of them. By undef'ing those 2 symbols, we ensure that the stdlib.h implementations are used. Thank you for these insights. I tried any number of things, but the `#undef malloc` [download] idea was not one of them. I understand that XSUB.h or another Perl header file redefines malloc into a Perl function or macro which takes two arguments, but the thing which I still find confusing is that the error messages appear to be coming from `XSUB.h` yet the actual error is occurring within my C file libdeflate-one.c, so the error messages seem to assume that the error occurred on another line from where they actually did. Since the compiler is gcc it's not the fault of Microsoft Windows. Edit I have just spent a little time debugging another XS module on Strawberry Perl (for details see this diff) and I'd like to point out that `#undef realloc` [download] and probably `#undef calloc` [download] are also needed if the C code is using those as well. There is no error message from Windows, and the GDB backtrace looks like this: ok 1 - use Gzip::Zopfli; Thread 1 received signal SIGSEGV, Segmentation fault. 0x00000000658f0794 in perl532!Perl_drand48_r () from C:\Strawberry\per +l\bin\perl532.dll (gdb) bt #0 0x00000000658f0794 in perl532!Perl_drand48_r () from C:\Strawberry +\perl\bin\perl532.dll #1 0x0000000067948d63 in ?? () from C:\Users\ben\Documents\Gzip-Zopfl +i-0.01\blib\arch\auto\Gzip\Zopfli\Zopfli.xs.dll #2 0x000000006794985a in ?? () from C:\Users\ben\Documents\Gzip-Zopfl +i-0.01\blib\arch\auto\Gzip\Zopfli\Zopfli.xs.dll #3 0x0000000067949964 in ?? () from C:\Users\ben\Documents\Gzip-Zopfl +i-0.01\blib\arch\auto\Gzip\Zopfli\Zopfli.xs.dll #4 0x0000000067949bf4 in ?? () from C:\Users\ben\Documents\Gzip-Zopfl +i-0.01\blib\arch\auto\Gzip\Zopfli\Zopfli.xs.dll #5 0x000000006587b1e2 in perl532!Perl_clear_defarray () from C:\Straw +berry\perl\bin\perl532.dll #6 0x00000000658dfdd6 in perl532!Perl_runops_standard () from C:\Stra +wberry\perl\bin\perl532.dll #7 0x0000000065890eb7 in perl_run () from C:\Strawberry\perl\bin\perl +532.dll #8 0x00000000658f3ac8 in perl532!RunPerl () from C:\Strawberry\perl\b +in\perl532.dll #9 0x00000000004013c7 in ?? () #10 0x00000000004014fb in ?? () #11 0x00007ffe753d7034 in KERNEL32!BaseThreadInitThunk () from C:\WIND +OWS\System32\kernel32.dll #12 0x00007ffe764bd241 in ntdll!RtlUserThreadStart () from C:\WINDOWS\ +SYSTEM32\ntdll.dll #13 0x0000000000000000 in ?? () Backtrace stopped: previous frame inner to this frame (corrupt stack?) [download] I found out what was wrong by Googling and puzzling over this bug report. It took a few attempts before I thought of this realloc problem.	[reply] [d/l] [select]


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