[cmake-developers] [CMake 0012390]: Parse output from <pkgname>-config binaries for -I/-L/-l flags

[Mantis Bug Tracker]

The following issue has been SUBMITTED. 
====================================================================== 
http://public.kitware.com/Bug/view.php?id=12390 
====================================================================== 
Reported By:                Martin von Gagern
Assigned To:                
====================================================================== 
Project:                    CMake
Issue ID:                   12390
Category:                   Modules
Reproducibility:            always
Severity:                   feature
Priority:                   normal
Status:                     new
====================================================================== 
Date Submitted:             2011-08-07 09:04 EDT
Last Modified:              2011-08-07 09:04 EDT
====================================================================== 
Summary:                    Parse output from <pkgname>-config binaries for
-I/-L/-l flags
Description: 
There are many packages that install a <name>-conf of <name>-config binary which
will generate cppflags/cflags and libs output, intended for use by depending
packages in their configure or make phase. In cases where the package doesn't
install a pkgconfig file as well, parsing the output of these commands is the
most portable way to correctly use these packages.

CMake doesn't deal directly in compiler flags, though. So in order to turn this
output into something cmake can handle properly, some parsing is required.
Therefore I'd like to see a function that can turn the string
" -O2 -I\"/usr/include\"/foo -DFOO_VERSION=1.1  -I'/usr/include/some bar' \n"
into the CMake list
"/usr/include/foo;/usr/include/some bar"

So given a specific flag, -I in this case, it should filter out all arguments
not starting with this flag, it should strip the flag from the remaining
arguments, and it should combine the resulting items to a ;-separated list. It
should remove quotes and preserve quoted spaces. The handling of spaces is
particularly tricky, and probably broken in most ad-hoc solutions out there.

I'm not sure whether executing the binary and parsing its output should be a
single step. Probably not, as the output for --libs should usually be parsed
twice, once for -L library directories and once for -l library names. So a
single command to do the parsing would be better. The flag to search for should
be an argument to that command. But for the common cases -I,-L and -l you might
want to add additional commands. That way, if you are running on a system which
conventionally uses other flags instead of these well-known ones, you might
search for these in addition to or instead of the common ones.

I guess the quotes-aware word splitting thing could be useful in other places as
well, so having it as a separate function might be useful.

Additional Information: 
The following CMake modules already do something like outlined above:
FindFLTK.cmake
FindFLTK2.cmake
FindGDAL.cmake
FindwxWidgets.cmake
FindXMLRPC.cmake

CMakeParseImplicitLinkInfo.cmake also does some parsing of linker command lines

Most of the above use something like STRING(REGEX REPLACE " +" ";" ...), and
therefore won't handle quoted spaces properly.
====================================================================== 

Issue History 
Date Modified    Username       Field                    Change               
====================================================================== 
2011-08-07 09:04 Martin von GagernNew Issue                                    
======================================================================