[CMake] ADD_CUSTOM_COMMAND issues

[Brandon Van Every]

On 7/13/07, Yegor Yefremov <yegor_sub1 at visionsystems.de> wrote:
> Hello,
>
> I want to use ADD_CUSTOM_COMMAND to create tags when building the
> project. The first problem, ADD_CUSTOM_COMMAND must be placed after the
> target definition. Should it be so?

Yes.  And it's reasonable, given that you're doing a POST_BUILD command.

> One can parse the CMakeLists.txt and
> build dependencies so that it doesn't matter where to place
> ADD_CUSTOM_COMMAND.

Kitware could comment on how difficult it would be to change their
implementation, but I anticipate the answer would be "very difficult."

> The second issue is that COMMENT won't be printed at all. A didn't use
> APPEND.
> [Citation from http://www.cmake.org/HTML/Documentation.html]:
>
> The COMMENT, WORKING_DIRECTORY, and MAIN_DEPENDENCY options are
> currently ignored when APPEND is given, but may be used in the future.
>
> But for me it is not the case.
>
> Best regards,
> Yegor Yefremov
>
> project (TEST)
>
> # some parameters
> set (CMAKE_VERBOSE_MAKEFILE OFF)
>
> # sources
> set (SRCS test.c)
>
> add_custom_command (TARGET test POST_BUILD COMMAND ctags -R WORKING_DIRECTORY ${HWTEST_SOURCE_DIR} COMMENT "Creating tags" VERBATIM)
> # executables
> add_executable (test ${SRCS})
>
> #include <stdio.h>
>
> int main(int argc, char *argv)
> {
>   printf("Hello world\n");
>
>   return 1;
> }

Note to anyone cutting and pasting this code to try it out: first you
have to put the ADD_EXECUTABLE before the ADD_CUSTOM_COMMAND.  That
took me a minute to sift through.

I've noted the following weird behavior on the MinGW generator,
executing under a Windows 2000 command prompt.  I do not have ctags
installed on my system.  Running from a pristine out-of-source build
directory, the 1st time I execute "mingw32-make", I get errors as I
would expect.  The 2nd time, I don't.  Then if I do "mingw32-make
clean", followed by "mingw32-make", I get errors as I would expect.
Errors only get reported once per build.

So could this explain why your commands seem to be "not working?"
What happens when you first execute in a pristine out-of-source build
directory?

C:\devel\mingw>cd append

C:\devel\mingw\append>mingw32-make
Scanning dependencies of target test
[100%] Building C object CMakeFiles/test.dir/test.obj
Linking C executable test.exe
process_begin: CreateProcess(NULL, ctags -R, ...) failed.
make (e=2): The system cannot find the file specified.
mingw32-make[2]: *** [test.exe] Error 2
mingw32-make[1]: *** [CMakeFiles/test.dir/all] Error 2
mingw32-make: *** [all] Error 2

C:\devel\mingw\append>mingw32-make
[100%] Built target test

C:\devel\mingw\append>mingw32-make clean

C:\devel\mingw\append>mingw32-make
[100%] Building C object CMakeFiles/test.dir/test.obj
Linking C executable test.exe
process_begin: CreateProcess(NULL, ctags -R, ...) failed.
make (e=2): The system cannot find the file specified.
mingw32-make[2]: *** [test.exe] Error 2
mingw32-make[1]: *** [CMakeFiles/test.dir/all] Error 2
mingw32-make: *** [all] Error 2

C:\devel\mingw\append>



Cheers,
Brandon Van Every