https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65083
Bug ID: 65083
Summary: Can not indirectly call some C11 atomic library
functions
Product: gcc
Version: 4.9.2
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: bin.x.fan at oracle dot com
C11 defines these as actual functions, not generic functions or macros:
atomic_thread_fence
atomic_signal_fence
atomic_flag_test_and_set
atomic_flag_test_and_set_explicit
atomic_flag_clear
atomic_flag_clear_explicit
User should be able to take their address and call them indirectly. However,
GCC does not provide definitions of these functions in libatomic.so, so GCC
does not allow the user to take the address of these functions.
Here is an example:
-bash-4.1$ gcc -v
Using built-in specs.
COLLECT_GCC=/net/dv104/export/tools/gcc/4.9.2/sparc-S2/bin/gcc.bin
COLLECT_LTO_WRAPPER=/net/dv104/export/tools/gcc/4.9.2/sparc-S2/libexec/gcc/sparc-sun-solaris2.10/4.9.2/lto-wrapper
Target: sparc-sun-solaris2.10
Configured with: ../gcc-4.9.2/configure
--prefix=/net/dv104/export/tools/gcc/4.9.2/sparc-S2
--enable-languages=c,c++,fortran
--with-gmp=/net/dv104/export/tools/gcc/4.9.2/sparc-S2
--with-mpfr=/net/dv104/export/tools/gcc/4.9.2/sparc-S2
--with-mpc=/net/dv104/export/tools/gcc/4.9.2/sparc-S2
Thread model: posix
gcc version 4.9.2 (GCC)
-bash-4.1$ cat t.c
#include <stdatomic.h>
void (*func_ptr) (memory_order order);
int main()
{
func_ptr = &atomic_thread_fence;
(*func_ptr)(memory_order_seq_cst);
return 0;
}
-bash-4.1$ gcc t.c -latomic
t.c: In function 'main':
t.c:5:15: error: 'atomic_thread_fence' undeclared (first use in this function)
func_ptr = &atomic_thread_fence;
^
t.c:5:15: note: each undeclared identifier is reported only once for each
function it appears in
