[Mingw-users] Linux toolchain, pthreads-win32

[Tatsh <dd...@gm...>]

Googling around it seems this question has been asked a lot but I still cannot
figure out exactly what is going wrong here.

I have a working GCC cross-compiler. Linking to many libs works fine.

$ i686-pc-mingw32-gcc -v
Using built-in specs.
Target: i686-pc-mingw32
Configured with:
/var/tmp/portage/cross-i686-pc-mingw32/gcc-4.4.3/work/gcc-4.4.3/configure
--prefix=/usr --bindir=/usr/x86_64-pc-linux-gnu/i686-pc-mingw32/gcc-bin/4.4.3
--includedir=/usr/lib/gcc/i686-pc-mingw32/4.4.3/include
--datadir=/usr/share/gcc-data/i686-pc-mingw32/4.4.3
--mandir=/usr/share/gcc-data/i686-pc-mingw32/4.4.3/man
--infodir=/usr/share/gcc-data/i686-pc-mingw32/4.4.3/info
--with-gxx-include-dir=/usr/lib/gcc/i686-pc-mingw32/4.4.3/include/g++-v4
--host=x86_64-pc-linux-gnu --target=i686-pc-mingw32 --build=x86_64-pc-linux-gnu
--disable-altivec --disable-fixed-point --without-ppl --without-cloog
--enable-nls --without-included-gettext --with-system-zlib --disable-checking
--disable-werror --enable-secureplt --disable-libmudflap --disable-libssp
--enable-libgomp --enable-cld
--with-python-dir=/share/gcc-data/i686-pc-mingw32/4.4.3/python --with-arch=i686
--enable-languages=c,c++,java,fortran --with-sysroot=/usr/i686-pc-mingw32
--disable-bootstrap --disable-libgomp --with-bugurl=http://bugs.gentoo.org/
--with-pkgversion='Gentoo 4.4.3 p1.0'
Thread model: win32
gcc version 4.4.3 (Gentoo 4.4.3 p1.0)

I went to the (dated) pthreads-win32 site and got the pre-built files from:

ftp://sourceware.org/pub/pthreads-win32/prebuilt-dll-2-8-0-release/

Copied the following:

pthread.h -> /usr/i686-pc-mingw32/usr/include
sched.h -> /usr/i686-pc-mingw32/usr/include/
semaphore.h -> /usr/i686-pc-mingw32/usr/include/
libpthreadGC2.a -> /usr/i686-pc-mingw32/usr/lib
libpthreadGCE2.a -> /usr/i686-pc-mingw32/usr/lib
pthreadGC2.dll -> /usr/i686-pc-mingw32/usr/bin
pthreadGCE2.dll -> /usr/i686-pc-mingw32/usr/bin

Here is the code I found in an example I'm trying to test with (added
ptw32_processInitialize()):
// Start
#include <pthread.h>

#include <stdio.h>
#include <stdlib.h>

#define NUM_THREADS 5

void *print_hello(void *thread_id) {
  long tid;
  tid = (long)thread_id;
  printf("Thread #%ld responding.\n", tid);
  pthread_exit(NULL);
}

int main(int argc, char *argv[]) {
  pthread_t threads[NUM_THREADS];
  int rc;
  long i;

  ptw32_processInitialize();

  for (i = 0; i < NUM_THREADS; i++) {
    printf("In main: creating thread %ld\n", i);
    rc = pthread_create(&threads[i], NULL, print_hello, (void *)i);
    if (rc) {
      printf("Error: return code from pthread_create() is %d\n", rc);
      exit(-1);
    }
  }
  pthread_exit(NULL);

  exit(EXIT_SUCCESS);
}
// End

Output is like this:
tatsh@tatshbook:~/dev-tutorials/pthreads-win32$ i686-pc-mingw32-gcc -o
example.exe -g -mthreads -DPTW32_STATIC_LIB -lpthreadGC2 example.c
/tmp/cca6ndLi.o: In function `print_hello':
/home/tatsh/dev-tutorials/pthreads-win32/example.c:11: undefined reference to
`_pthread_exit'
/tmp/cca6ndLi.o: In function `main':
/home/tatsh/dev-tutorials/pthreads-win32/example.c:19: undefined reference to
`_ptw32_processInitialize'
/home/tatsh/dev-tutorials/pthreads-win32/example.c:22: undefined reference to
`_pthread_create'
/home/tatsh/dev-tutorials/pthreads-win32/example.c:28: undefined reference to
`_pthread_exit'
collect2: ld returned 1 exit status

Without -DPTW32_STATIC_LIB then undefined references turn from _pthread_exit to
__imp_pthread_exit for example.

I am not sure to do. One clue was to have the call to ptw32_processInitialize()
but this has just added another undefined reference. Clearly the headers are
found but the linker is not finding these lib files.

Thanks
-- 
Tatsh
www.tatsh.net
dd...@gm...