[CMake] Simple question

[Brad King]

Luca Cappa wrote:
> Well, i would like also to know if it is possible to set the value of a 
> variable to the output of a command, i.e. how to put the output of 
> "pkg-config --cflags --libs gtkmm" in the variable directly.
>> Is this the right way to add some values to a variable?
>>
>> SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} `pkg-config --cflags --libs 
>> gtkmm`")

Use the EXEC_PROGRAM command and then use the CACHE option of the SET 
command to save the output to a variable like GTK_PKG_FLAGS.  Then use 
the SET command to add the value.  Something like this:

IF(NOT GTK_PKG_FLAGS)
   EXEC_PROGRAM(pkg-config ARGS --cflags --libs gtkmm
                OUTPUT_VARIABLE GTK_PKG_FLAGS)
   SET(GTK_PKG_FLAGS "${GTK_PKG_FLAGS}" CACHE STRING "GTK Flags")
ENDIF(NOT GTK_PKG_FLAGS)
SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${GTK_PKG_FLAGS}")

-Brad