Pascal Fleury wrote:
How do I figure out that mylib.(a|lib) needs, e.g., the ws2_32.lib on Windows
or the sockets.so on linux ? I just found the mylib_LIB_DEPENDS variable in
the cache, but it is in a section that says internal, and it does not seem to
be the portable way to do it.
The autotools way would be to write a test program, and use TRY_COMPILE
to walk a list of libraries that might allow the program to compile.
From that, you set a variable to the name of the library that provides
the needed feature, and then use either LINK_LIBRARIES (not preferred)
or TARGET_LINK_LIBRARIES.
In my project, I wrote this macro:
MACRO(CHECK_LIBRARY LIB_NAME LIB_DESC LIB_TEST_SOURCE)
SET(HAVE_${LIB_NAME})
MESSAGE(STATUS "Checking for ${LIB_DESC} library...")
TRY_COMPILE(HAVE_${LIB_NAME} ${CMAKE_BINARY_DIR}/.cmake_temp
${CMAKE_SOURCE_DIR}/cmake/${LIB_TEST_SOURCE})
IF(HAVE_${LIB_NAME})
# Don't need one
MESSAGE(STATUS "Checking for ${LIB_DESC} library... none needed")
ELSE(HAVE_${LIB_NAME})
# Try to find a suitable library
FOREACH(lib ${ARGN})
TRY_COMPILE(HAVE_${LIB_NAME} ${CMAKE_BINARY_DIR}/.cmake_temp
${CMAKE_SOURCE_DIR}/cmake/${LIB_TEST_SOURCE}
CMAKE_FLAGS -DLINK_LIBRARIES:STRING=${lib})
IF(HAVE_${LIB_NAME})
MESSAGE(STATUS "Checking for ${LIB_DESC} library...
${lib}")
SET(HAVE_${LIB_NAME}_LIB ${lib})
ENDIF(HAVE_${LIB_NAME})
ENDFOREACH(lib)
ENDIF(HAVE_${LIB_NAME})
# Unable to find a suitable library
IF(NOT HAVE_${LIB_NAME})
MESSAGE(STATUS "Checking for ${LIB_DESC} library... not found")
ENDIF(NOT HAVE_${LIB_NAME})
ENDMACRO(CHECK_LIBRARY)
...the LIB_NAME param controls the name of the variable(s) that are set
if it finds the library. LIB_DESC is used for the status messages. An
example usage might be:
CHECK_LIBRARY(SCK socket scktest.c socket xnet ws2_32)
(xnet is IIRC the lib used on Solaris, which illustrates why you
probably shouldn't just use something based on IF(UNIX)/IF(WIN32).)
I don't know if there is a canonical better way; there is
CHECK_FUNCTION_EXISTS, but I can imagine that tripping up on some
platform where the function seems to exist but can't be called.
There certainly might be a module for any particular library you are
interested in.
--
Matthew
PIE INCOMING!!!
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