Alexander Neundorf wrote:
On Thursday 02 October 2008, Matthew Woehlke wrote:
Is there a standard way to find the library needed for a particular
function, when possibly none is needed? For example, gethostbyname might
be provided in libc, libnsl, libsocket, etc. on various platforms.
I've found myself a couple times now writing a macro to do this, but I
wonder if there is a standard way? If not, would this possibly be a good
module to add?
Here's my most recent incarnation, which piggybacks on the existing
CheckFunctionExists module (borrows its test source). This takes the
name of the variable to receive the required library (may be empty), the
name of the function to look for, and a list of libraries that might
contain the function. It first tries with no additional libraries to see
if the default libraries suffice.
Nice idea :-)
macro(find_library_sym var sym)
message(STATUS "Checking what library is needed for ${sym}")
try_compile(HAVE_${sym} ${CMAKE_BINARY_DIR}
${CMAKE_ROOT}/Modules/CheckFunctionExists.c
COMPILE_DEFINITIONS -DCHECK_FUNCTION_EXISTS=${sym}
)
if(HAVE_${sym})
# No library needed
message(STATUS ""Checking what library is needed for ${sym} -
none")
else(HAVE_${sym})
foreach(lib ${ARGN})
set(CMAKE_REQUIRED_LIBRARIES ${lib})
Is the line above actually necessary ?
I think not.
Oops, no, that's left over from when I was using CheckFunctionExists
instead of my own try_compile (the existing module is too noisy for
calling several times). Thanks for spotting that, I removed it from my
own sources also :-).
But instead the module should support the same CMAKE_REQUIRED_* variables as
CheckFunctionExists.cmake does.
Sure. I didn't say it was polished :-). It does what I need it, where I
need it. As a proper module, it a start, but would need more integration.
--
Matthew
Please do not quote my e-mail address unobfuscated in message bodies.
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