[CMake] Finding a pkg-config file

[Alan W. Irwin]

On 2018-09-21 15:55+0200 Florian Lindner wrote:

> Hello,
>
> on a really weird configured system (but I can't change it), there is a pkg-config file which I want to find with cmake:
>
>  set(ENV{PKG_CONFIG_PATH} "$ENV{PKG_CONFIG_PATH}:$ENV{PETSC_DIR}/lib/pkgconfig")
>  set(CMAKE_PREFIX_PATH "$ENV{PETSC_DIR}/lib/pkgconfig")
>  find_package(PkgConfig REQUIRED)
>  pkg_check_modules(PETSC REQUIRED craypetsc_real)
>
> but
>
> -- Checking for module 'craypetsc_real'
> --   No package 'craypetsc_real' found
> CMake Error at /usr/share/cmake/Modules/FindPkgConfig.cmake:363 (message):
>  A required package was not found
>
>
>
>> cat $PETSC_DIR/lib/pkgconfig/craypetsc_real.pc
>
> VERSION=3.8.4.0
> PE=GNU
> pe=gnu
> GENCOMP=7.1
> CPU_TARGET=haswell
>
> install_prefix=/opt/cray/pe
> root=${install_prefix}/petsc/3.8.4.0/real
> prefix=${root}/${PE}/${GENCOMP}/${CPU_TARGET}
> libdir=${prefix}/lib
> includedir=${prefix}/include
>
> cray_as_needed=
> cray_no_as_needed=
>
> Name: craypetsc_real
> Description: Scientific libraries
> Version: ${VERSION}
> Libs: -L${libdir} ${cray_as_needed}-lcraypetsc_gnu_71_real${cray_no_as_needed}  -fopenmp
> Libs.private:
> Requires:
> Requires.private: mpich >= 7.0 sci_mp >= 13.0 cray-tpsl >= 16.03.1 hdf5_parallel
> Conflicts: hdf5
> Cflags:  -I${includedir}
>
> pkg-config also finds it:
>
>> PKG_CONFIG_PATH=$PETSC_DIR/lib/pkgconfig pkg-config --print-variables craypetsc_real
> cray_as_needed
> prefix
> libdir
> [...]
>
>
> CMakeError.log does not exist, CMakeOutput.log I have attached.

Hi Florian:

What happens if you set PKG_CONFIG_PATH outside cmake rather than inside?

e.g.,

env PKG_CONFIG_PATH=$PETSC_DIR/lib/pkgconfig cmake ....

with both

set(ENV{PKG_CONFIG_PATH} "$ENV{PKG_CONFIG_PATH}:$ENV{PETSC_DIR}/lib/pkgconfig")
set(CMAKE_PREFIX_PATH "$ENV{PETSC_DIR}/lib/pkgconfig")

commented out inside your CMakeList.txt file?

That method has always worked for me.  And if it works for you, then I would
think attempting to set the enviroment variable PKG_CONFIG_PATH inside
your CMakeLists.txt file with just

set(ENV{PKG_CONFIG_PATH} "$ENV{PKG_CONFIG_PATH}:$ENV{PETSC_DIR}/lib/pkgconfig")

(setting CMAKE_PREFIX_PATH should not be required) should just work, but it is
always possible (although I haven't checked documentation to see) there is
some incorrect syntax in that line so I would also use message to print
out the PKG_CONFIG_PATH environment variable to see what you have actually
set it to within CMake.

Alan
__________________________
Alan W. Irwin

Programming affiliations with the FreeEOS equation-of-state
implementation for stellar interiors (freeeos.sf.net); the Time
Ephemerides project (timeephem.sf.net); PLplot scientific plotting
software package (plplot.sf.net); the libLASi project
(unifont.org/lasi); the Loads of Linux Links project (loll.sf.net);
and the Linux Brochure Project (lbproject.sf.net).
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