[Buildroot] [PATCH] yajl: fix build with uClibc
Benoît Mauduit
bmauduit at beneth.fr
Fri Apr 22 13:58:26 UTC 2016
Hi Vicente, Jörg,
On 04/21/2016 08:15 AM, Jörg Krause wrote:
> (...)
>
> I'm not sure if it's worth, but I would prefer to fix the CMake build
> files of yajl by checking if libm is needed for isnan and it to the
> list of LIBS and let all executables link against LIBS. Thomas
> Petazzoni did this for an autotools package [3]. For CMake it would be
> something like this:
>
> # check if isnan needs libm
> try_compile(ISNAN_NEEDS_LIBM, ...)
> if (ISNAN_NEEDS_LIBM)
> set(LIBS ${LIBS} m)
> endif ()
>
> [..]
>
> TARGET_LINK_LIBRARIES(${testProg} yajl ${LIBS})
>
I just encountered this build issue.
I end up with a patch like that, in yasl Top-level CMakeList.txt :
# uclibc does not provide isnan() & isinf().
# Symbol are in libm instead.
INCLUDE(CheckLibraryExists)
CHECK_LIBRARY_EXISTS(c isnan "" HAVE_LIBC_ISNAN)
IF (NOT HAVE_LIBC_ISNAN)
SET(CMAKE_SHARED_LINKER_FLAGS "-lm ${CMAKE_SHARED_LINKER_FLAGS}")
ENDIF (NOT HAVE_LIBC_ISNAN)
It works with uClibc based toolchain.
But I am not sure about this patch for compatibility with other C
library. I have just test on my host (glibc) with a dummy CMakeList.txt,
and :
CHECK_LIBRARY_EXISTS(c isnan "" HAVE_LIBC_ISNAN)
>>
-- Looking for isnan in c
-- Looking for isnan in c - found
Anyway, looking at the man page for isnan & isinf, we are supposed to
link against libmath... (Link with -lm)
Regards,
--
Benoît Mauduit
Mail : <bmauduit at beneth.fr>
XMPP : <bmauduit at im.beneth.fr>
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