[CMake] Suppressing a compilation option for one file?

[Bill Hoffman]

Bryan O'Sullivan wrote:
> I know that I can use set_source_files_properties to add to the 
> compilation flags used to build a single source file, but is there a way 
> to *remove* a compilation flag for one file?
> 
> My problem is that I build the source tree with -Wall -Werror, but one 
> source file contains a use of a bad macro from a third party package for 
> which there's no gcc option to override the warning that gets generated, 
> so I need to turn off -Werror instead.
> 
Not easily....

You could do something like remove the -Werror from the flags, and add 
it into the files that need it.


Something like:

# remove -Werror from CMAKE_CXX_FLAGS and save it
# in EXTRA_FLAG if found
if(CMAKE_CXX_FLAGS MATCHES -Werror)
   replace -Werror in CMAKE_CXX_FLAGS with ""
   set(EXTRA_FLAG -Werror)
...

# if there is an EXTRA_FLAG, add it to all the source files
# except the ones that don't need it.
if(EXTRA_FLAG)
   foreach(f ${SOURCES})
    if(f NOT somefile)
      set_source_files_properties(f1 COMPILE_FLAGS ${EXTRA_FLAG})

-Bill