Re: Tests on MinGW: undef ref pthread_mutex_lock/unlock

[Eric Blake]

On 4/11/19 7:26 PM, Bruno Haible wrote:

> Btw, I never build with mingw-pthreads installed. But even with mingw-pthreads
> installed, gnulib modules ought to not use it; they ought to use the Windows
> API instead.

Jumping in late, but this reminded me of a patch I wrote years ago:

https://libvirt.org/git/?p=libvirt.git;a=commitdiff;h=c91d13bd

> On my Fedora 20 box with mingw cross-compiler, the build failed with:
> 
> ../../src/rpc/virnetclient.c: In function 'virNetClientSetTLSSession':
> ../../src/rpc/virnetclient.c:745:14: error: unused variable 'oldmask' 
> [-Werror=unused-variable]
>      sigset_t oldmask, blockedsigs;
>               ^
> 
> I traced it to the fact that mingw64-winpthreads installs a header
> that does #define pthread_sigmask(...) 0, which means any argument
> only ever passed to pthread_sigmask is reported as unused.  This
> patch works around the compilation failure, with behavior no worse
> than what mingw already gives us regarding the function being a
> no-op.
> 
> * configure.ac (pthread_sigmask): Probe for broken mingw macro.
> * src/util/virutil.h (pthread_sigmask): Rewrite to something that
> avoids unused variables.

Here we are 5 years later, and mingw32-winpthreads-5.0.4-2.fd29 still
has a broken:

/usr/i686-w64-mingw32/sys-root/mingw/include/pthread_signal.h:
#define pthread_sigmask(H, S1, S2) 0

So indeed, gnulib could do a better job at avoiding that library as more
pain than it is worth.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org

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