From 10fee6d71a1f7d6e6319005196562b4a30b4e8ff Mon Sep 17 00:00:00 2001 From: Thomas Petazzoni Date: Tue, 2 Feb 2016 14:58:52 +0100 Subject: [PATCH] Fix detection of C11 atomics Currently, the CMakeLists.txt logic to detect the availability of C11 atomics is based on building a small program that uses the atomic_load(). However, atomic_load() does not need to use any function from libatomic (part of the gcc runtime). So even if libatomic is missing, this test concludes that C11 atomic support is available. For example on SPARC, the example program builds fine without linking to libatomic, but calling other functions of the atomic_*() APIs fail without linking to libatomic. So, this patch adjusts the CMakeLists.txt test to use a function that is known to require the libatomic run-time library (on architectures where it is needed). This way, openal will only use the __atomic_*() built-ins when they are actually functional. Signed-off-by: Thomas Petazzoni --- CMakeLists.txt | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/CMakeLists.txt b/CMakeLists.txt index 5784d35..a53f996 100644 --- a/CMakeLists.txt +++ b/CMakeLists.txt @@ -209,14 +209,17 @@ CHECK_C_SOURCE_COMPILES( HAVE_C11_ALIGNAS) # Check if we have C11 _Atomic +set(OLD_REQUIRED_LIBRARIES ${CMAKE_REQUIRED_LIBRARIES}) +set(CMAKE_REQUIRED_LIBRARIES ${EXTRA_LIBS}) CHECK_C_SOURCE_COMPILES( "#include - const int _Atomic foo = ATOMIC_VAR_INIT(~0); + int _Atomic foo = ATOMIC_VAR_INIT(~0); int main() { - return atomic_load(&foo); + return atomic_fetch_add(&foo, 2); }" HAVE_C11_ATOMIC) +set(CMAKE_REQUIRED_LIBRARIES ${OLD_REQUIRED_LIBRARIES}) # Add definitions, compiler switches, etc. INCLUDE_DIRECTORIES("${OpenAL_SOURCE_DIR}/include" "${OpenAL_BINARY_DIR}") -- 2.6.4