Linking to Pthreads - Undefined References With Mingw

[Tonto]

I'm trying to use pthreads and am getting undefined references. Here's the command line

C:/Bin/Mingw/bin/../libexec/gcc/mingw32/3.4.2/collect2.exe -Bdynamic -o Stktest.exe 
    C:/Bin/Mingw/bin/../lib/gcc/mingw32/3.4.2/../../../crt2.o 
    C:/Bin/Mingw/bin/../lib/gcc/mingw32/3.4.2/crtbegin.o 

    -LC:\Bin\Stk\bin -LC:\Bin\Mingw\Lib -LC:\Bin\Pthreads\lib 
    -LC:/Bin/Mingw/bin/../lib/gcc/mingw32/3.4.2 
    -LC:/Bin/Mingw/bin/../lib/gcc 
    -LC:/Bin/Mingw/bin/../lib/gcc/mingw32/3.4.2/../../../../mingw32/lib 
    -LC:/Bin/Mingw/bin/../lib/gcc/mingw32/3.4.2/../../.. 

    Debug\stdafx.o Debug\Stktest.o 
    -lpthreadGC2 -lstk -lstdc++ -lmingw32 -lgcc -lmoldname -lmingwex -lmsvcrt 
    -luser32 -lkernel32 -ladvapi32 -lshell32 -lmingw32 -lgcc -lmoldname -lmingwex  -lmsvcrt 

    C:/Bin/Mingw/bin/../lib/gcc/mingw32/3.4.2/crtend.o

C:\Bin\Stk\bin/libstk.a(RtAudio.o): In function `ZN5RtApiD0Ev':C:/Bin/Stk/src/RtAudio.cpp:263: undefined reference to `_imp__pthread_mutex_destroy'
C:\Bin\Stk\bin/libstk.a(RtAudio.o): In function `ZN5RtApiD1Ev':C:/Bin/Stk/src/RtAudio.cpp:263: undefined reference to `_imp__pthread_mutex_destroy'
C:\Bin\Stk\bin/libstk.a(RtAudio.o): In function `ZN5RtApiD2Ev':C:/Bin/Stk/src/RtAudio.cpp:263: undefined reference to `_imp__pthread_mutex_destroy'
C:\Bin\Stk\bin/libstk.a(RtAudio.o): In function `ZN5RtApiC1Ev':C:/Bin/Stk/src/RtAudio.cpp:258: undefined reference to `_imp__pthread_mutex_init'
C:\Bin\Stk\bin/libstk.a(RtAudio.o): In function `ZN5RtApiC2Ev':C:/Bin/Stk/src/RtAudio.cpp:258: undefined reference to `_imp__pthread_mutex_init'

Here's the dumpbin of the pthreads library I'm linking against

C:\Bin\Pthreads\lib>dumpbin libpthreadGC2.a /exports
Microsoft (R) COFF/PE Dumper Version 8.00.50727.762
Copyright (C) Microsoft Corporation.  All rights reserved.


Dump of file libpthreadGC2.a

File Type: LIBRARY

     Exports

       ordinal    name

                  _sem_wait
                  _sem_unlink
                  _sem_trywait
                  _sem_timedwait
                  _sem_post_multiple
                  ...
                  _pthread_mutexattr_destroy
                  _pthread_mutex_unlock
                  _pthread_mutex_trylock
                  _pthread_mutex_timedlock
                  _pthread_mutex_lock
                  _pthread_mutex_init
                  _pthread_mutex_destroy
                  ...

  Summary

           0 .bss
           0 .data
          14 .idata$2
         1D4 .idata$4
         1D4 .idata$5
         B10 .idata$6
         1DC .idata$7
         398 .text

C:\Bin\Pthreads\lib>

A similar thread I found was here: http://sourceware.org/ml/pthreads-wi.../msg00056.html
Answer here: http://sourceware.org/ml/pthreads-wi.../msg00058.html

But the case of link order doesn't seem to be the issue, but my dumpbin doesn't contain these '_imp_xxx' references, so I'm not exactly sure what to do

[brewbuck]

But the case of link order doesn't seem to be the issue, but my dumpbin doesn't contain these '_imp_xxx' references, so I'm not exactly sure what to do

Have you actually TRIED putting it last on the link line? Libraries often contain weak symbols which alias other symbols in the library. The _imp_xxx symbols might be there, but dumpbin isn't showing them.

[Tonto]

Ah that is very interesting (I only dumped the exports, didn't know I should look at anything else)

String Table Size = 0x5D bytes

COFF SYMBOL TABLE
000 00000000 SECT1  notype       Static       | .text
001 00000000 SECT2  notype       Static       | .data
002 00000000 SECT3  notype       Static       | .bss
003 00000000 SECT4  notype       Static       | .idata$7
004 00000000 SECT5  notype       Static       | .idata$5
005 00000000 SECT6  notype       Static       | .idata$4
006 00000000 SECT7  notype       Static       | .idata$6
007 00000000 SECT1  notype       External     | _pthread_mutexattr_init
008 00000000 SECT5  notype       External     | __imp__pthread_mutexattr_init
009 00000000 UNDEF  notype       External     | __head_libpthreadGC2_a


String Table Size = 0x49 bytes

COFF SYMBOL TABLE
000 00000000 SECT1  notype       Static       | .text
001 00000000 SECT2  notype       Static       | .data
002 00000000 SECT3  notype       Static       | .bss
003 00000000 SECT4  notype       Static       | .idata$7
004 00000000 SECT5  notype       Static       | .idata$5
005 00000000 SECT6  notype       Static       | .idata$4
006 00000000 SECT7  notype       Static       | .idata$6
007 00000000 SECT1  notype       External     | _pthread_mutex_destroy
008 00000000 SECT5  notype       External     | __imp__pthread_mutex_destroy
009 00000000 UNDEF  notype       External     | __head_libpthreadGC2_a

>> Have you actually TRIED putting it last on the link line?

Yeah I don't know how I read it this way but I just thought it meant after the object files on the command line. Sorry about that, it now compiles perfectly. Gahd I'm thickheaded.

>> Libraries often contain weak symbols which alias other symbols in the library.

Cool, I didn't know that.

[brewbuck]

Yeah I don't know how I read it this way but I just thought it meant after the object files on the command line. Sorry about that, it now compiles perfectly. Gahd I'm thickheaded.

The exact error message was a clue:

C:\Bin\Stk\bin/libstk.a(RtAudio.o): In function `ZN5RtApiD0Ev':C:/Bin/Stk/src/RtAudio.cpp:263: undefined reference to `_imp__pthread_mutex_destroy'

The undefined reference is in libstk.a, NOT your code. That means the pthreads library had to be listed AFTER libstk on the link line.

Pay attention to the error messages ;-)