Re: Why configure failed to search libws2_32.a in MinGW+MSYS ?

[Guo Leaveye]

Thanks a lot for your tip.

Acoording to the log file, it just compiles a source code like this, I only 
keep the lines matters.

    char WSAGetLastError ();
    int
    main ()
    {
    return WSAGetLastError ();
    }

When compiling this simple source, GCC reports a error that "undefined 
reference to `WSAGetLastError'", even though there is a linker option 
"-lws2_32". I tried to replace the declaration of WSAGetLastError() with 
includes of windows.h and winsock2.h, then it works. I have no idea on this 
behaviour, that why linking the same library leads different result. Is there 
any advice ?

BTW, here is the error output by GCC with option "-v".

> $ gcc -o out.exe -g -O2 testlib.c -lws2_32 -v
>  specs
> COLLECT_GCC=D:\MinGW\bin\gcc.exe
> COLLECT_LTO_WRAPPER=d:/mingw/bin/../libexec/gcc/mingw32/4.6.2/lto-wrapper.exe
> mingw32
> ../gcc-4.6.2/configure --enable-languages=c,c++,ada,fortran,objc,obj-c++ 
> --disable-sjlj-exceptions -
> -with-dwarf2 --enable-shared --enable-libgomp --disable-win32-registry 
> --enable-libstdcxx-debug --en
> able-version-specific-runtime-libs --build=mingw32 --prefix=/mingw
> win32
> gcc  4.6.2 (GCC)
> COLLECT_GCC_OPTIONS='-o' 'out.exe' '-g' '-O2' '-v' '-mtune=i386' '-march=i386'
>  d:/mingw/bin/../libexec/gcc/mingw32/4.6.2/cc1.exe -quiet -v -iprefix 
> d:\mingw\bin\../lib/gcc/mingw3
> 2/4.6.2/ testlib.c -quiet -dumpbase testlib.c -mtune=i386 -march=i386 
> -auxbase testlib -g -O2 -versi
> on -o C:\Users\ADMINI~1\AppData\Local\Temp\cc6Urmwg.s
> GNU C (GCC)  4.6.2 (mingw32)
>          GNU C  4.6.2 GMP  5.0.1MPFR  2.4.1MPC  0.8.1
> GGC --param ggc-min-expand=100 --param ggc-min-heapsize=131072
> d:\mingw\bin\../lib/gcc/mingw32/4.6.2/../../../../mingw32/include
> d:/mingw/lib/gcc/../../lib/gcc/mingw32/4.6.2/include
> /mingw/lib/gcc/mingw32/4.6.2/../../../../include
> d:/mingw/lib/gcc/../../include
> d:/mingw/lib/gcc/../../lib/gcc/mingw32/4.6.2/include-fixed
> d:/mingw/lib/gcc/../../lib/gcc/mingw32/4.6.2/../../../../mingw32/include
> /mingw/include
> #include "..."
> #include <...>
>  d:\mingw\bin\../lib/gcc/mingw32/4.6.2/include
>  d:\mingw\bin\../lib/gcc/mingw32/4.6.2/../../../../include
>  d:\mingw\bin\../lib/gcc/mingw32/4.6.2/include-fixed
> 
> GNU C (GCC)  4.6.2 (mingw32)
>          GNU C  4.6.2 GMP  5.0.1MPFR  2.4.1MPC  0.8.1
> GGC --param ggc-min-expand=100 --param ggc-min-heapsize=131072
> Compiler executable checksum: c20aed7c018482d7b62efcd5dcab2a9d
> COLLECT_GCC_OPTIONS='-o' 'out.exe' '-g' '-O2' '-v' '-mtune=i386' '-march=i386'
>  d:/mingw/bin/../lib/gcc/mingw32/4.6.2/../../../../mingw32/bin/as.exe -o 
> C:\Users\ADMINI~1\AppData\L
> ocal\Temp\ccFvAZop.o C:\Users\ADMINI~1\AppData\Local\Temp\cc6Urmwg.s
> COMPILER_PATH=d:/mingw/bin/../libexec/gcc/mingw32/4.6.2/;d:/mingw/bin/../libexec/gcc/;d:/mingw/bin/.
> ./lib/gcc/mingw32/4.6.2/../../../../mingw32/bin/
> LIBRARY_PATH=d:/mingw/bin/../lib/gcc/mingw32/4.6.2/;d:/mingw/bin/../lib/gcc/;d:/mingw/bin/../lib/gcc
> /mingw32/4.6.2/../../../../mingw32/lib/;d:/mingw/bin/../lib/gcc/mingw32/4.6.2/../../../;/mingw/lib/
> COLLECT_GCC_OPTIONS='-o' 'out.exe' '-g' '-O2' '-v' '-mtune=i386' '-march=i386'
>  d:/mingw/bin/../libexec/gcc/mingw32/4.6.2/collect2.exe -Bdynamic -o out.exe 
> d:/mingw/bin/../lib/gcc
> /mingw32/4.6.2/../../../crt2.o 
> d:/mingw/bin/../lib/gcc/mingw32/4.6.2/crtbegin.o -Ld:/mingw/bin/../li
> b/gcc/mingw32/4.6.2 -Ld:/mingw/bin/../lib/gcc 
> -Ld:/mingw/bin/../lib/gcc/mingw32/4.6.2/../../../../mi
> ngw32/lib -Ld:/mingw/bin/../lib/gcc/mingw32/4.6.2/../../.. -L/mingw/lib 
> C:\Users\ADMINI~1\AppData\Lo
> cal\Temp\ccFvAZop.o -lws2_32 -lmingw32 -lgcc_eh -lgcc -lmoldname -lmingwex 
> -lmsvcrt -ladvapi32 -lshe
> ll32 -luser32 -lkernel32 -lmingw32 -lgcc_eh -lgcc -lmoldname -lmingwex 
> -lmsvcrt d:/mingw/bin/../lib/
> gcc/mingw32/4.6.2/crtend.o
> C:\Users\ADMINI~1\AppData\Local\Temp\ccFvAZop.o: In function `main':
> d:\Projects\libisl\build/testlib.c:22: undefined reference to 
> `WSAGetLastError'
> collect2: ld  1

Regards.

Levi G.
Haskell is a beautiful language.

在 2013/12/28，上午7:18，Bob Friesenhahn <address@hidden> 写道：

> Look in the generated config.log for the errors produced while testing for 
> WSAGetLastError.  The errors may provide a clue as to what has actually gone 
> wrong and lead to fixing the problem.  Autoconf tests for library functions 
> by linking a small test program.  Sometimes it is necessary to supply 
> additional libraries in order to successfully link with a library.
> 
> Bob
> -- 
> Bob Friesenhahn
> address@hidden, http://www.simplesystems.org/users/bfriesen/
> GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/

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