mingw-users

[Mingw-users] error in compiling opencv 2.1 with gcc 4.5.0

[zwz <zha...@gm...>]

Hi, I just checked out the latest opencv 2.1 and generated the makefile
for msys.

And then I tried to compile it by gcc 4.5.0, with the error: 
[ 0%] Generating precomp.hpp.gch/opencv_imgproc_Release.gch
d:/gnu/mingw/bin/../lib/gcc/mingw32/4.5.0/../../../libmingw32.a(main.o):main.c:(.text+0xd2):
undefined reference to `WinMain@16' 
collect2: ld returned 1 exit status

However, if I turn to gcc 4.4.0, it compiles successfully.

I am quite confused now about where the problem is.
Is the error caused by opencv or gcc?

Re: [Mingw-users] error in compiling opencv 2.1 with gcc 4.5.0

[Cesar S. <ces...@gm...>]

On 13/5/2010 07:14, zwz wrote:
> [ 0%] Generating precomp.hpp.gch/opencv_imgproc_Release.gch
> d:/gnu/mingw/bin/../lib/gcc/mingw32/4.5.0/../../../libmingw32.a(main.o):main.c:(.text+0xd2):
> undefined reference to `WinMain@16'
> collect2: ld returned 1 exit status
>

Could you show the full gcc command line?

When generating a precompiled header, please make sure you do not have 
any linker flag on the command line or, if you do, use it together with 
-c. Example:

$ echo "extern int i;" > pch.h

$ gcc pch.h

(Success)

$ gcc -Wl,--enable-auto-import pch.h

c:/mingw/bin/../lib/gcc/mingw32/4.5.0/../../../libmingw32.a(main.o):main.c:(.text+0xd2): 
undefined reference to `WinMain@16'
collect2: ld returned 1 exit status

(Failure)

$ gcc -Wl,--enable-auto-import -c pch.h

(Success again)

Regards,
Cesar

Re: [Mingw-users] error in compiling opencv 2.1 with gcc 4.5.0

[zwz <zha...@gm...>]

Cesar Strauss <ces...@gm...>
writes:

> On 13/5/2010 07:14, zwz wrote:
>> [ 0%] Generating precomp.hpp.gch/opencv_imgproc_Release.gch
>>
> d:/gnu/mingw/bin/../lib/gcc/mingw32/4.5.0/../../../libmingw32.a(main.o):main.c:(.text+0xd2):
>> undefined reference to `WinMain@16'
>> collect2: ld returned 1 exit status
>>
>
> Could you show the full gcc command line?
>
> When generating a precompiled header, please make sure you do not have 
> any linker flag on the command line or, if you do, use it together with 
> -c. Example:
>
> $ echo "extern int i;" > pch.h
>
> $ gcc pch.h
>
> (Success)
>
> $ gcc -Wl,--enable-auto-import pch.h
>
> c:/mingw/bin/../lib/gcc/mingw32/4.5.0/../../../libmingw32.a(main.o):main.c:(.text+0xd2):
> undefined reference to `WinMain@16'
> collect2: ld returned 1 exit status
>
> (Failure)
>
> $ gcc -Wl,--enable-auto-import -c pch.h
>
> (Success again) 
Thanks for the tips. 
The error was produced with the flags
"-Wl,--enable-runtime-pseudo-reloc-v2" 
during the configuration of CMAKE.

If I added the the flag "-c", then it compiles
but cannot be linked.

I can remove all the flags and compile it
but then when I run the cvtest.exe, it reported "initialize
0xc0000005 error"

>
> Regards,
> Cesar
>
>
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