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/*
* compiler.h - compiler specific macros
*
* This software is distributed under a BSD-style license. See the
* file "COPYING" in the toop-level directory of the distribution for details.
*/
#ifndef _GPSD_COMPILER_H_
#define _GPSD_COMPILER_H_
/*
* Tell GCC that we want thread-safe behavior with _REENTRANT;
* in particular, errno must be thread-local.
* Tell POSIX-conforming implementations with _POSIX_THREAD_SAFE_FUNCTIONS.
* See http://www.unix.org/whitepapers/reentrant.html
*/
#ifndef _REENTRANT
#define _REENTRANT
#endif
#ifndef _POSIX_THREAD_SAFE_FUNCTIONS
#define _POSIX_THREAD_SAFE_FUNCTIONS
#endif
#include "gpsd_config.h" /* is HAVE_STDATOMIC defined? */
/* Macro for declaring function with printf-like arguments. */
# if __GNUC__ >= 3 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 7)
#define PRINTF_FUNC(format_index, arg_index) \
__attribute__((__format__(__printf__, format_index, arg_index)))
# else
#define PRINTF_FUNC(format_index, arg_indx)
#endif
/* Macro for declaring function arguments unused. */
#if defined(__GNUC__) || defined(__clang__)
#define UNUSED __attribute__((unused))
#else
#define UNUSED
#endif
/*
* Macro for compile-time checking if argument is an array.
* It expands to constant expression with int value 0.
*/
#if defined(__GNUC__)
#define COMPILE_CHECK_IS_ARRAY(arr) ( \
0 * (int) sizeof(({ \
struct { \
int unused_int; \
typeof(arr) unused_arr; \
} zero_init = {0}; \
typeof(arr) arg_is_not_array UNUSED = { \
zero_init.unused_arr[0], \
}; \
1; \
})) \
)
#else
#define COMPILE_CHECK_IS_ARRAY(arr) 0
#endif
/* Needed because 4.x versions of GCC are really annoying */
#define ignore_return(funcall) \
do { \
UNUSED ssize_t locresult = (funcall); \
assert(locresult != -23); \
} while (0)
#ifdef HAVE_STDATOMIC_H
#if !defined(__COVERITY__)
#if !defined(__cplusplus)
#include <stdatomic.h>
#elif __cplusplus >= 201103L
/* C++ before C++11 can not handle stdatomic.h or atomic */
/* atomic is just C++ for stdatomic.h */
#include <atomic>
#endif /* __cplusplus */
#endif /* __COVERITY__ */
#endif /* HAVE_STDATOMIC_H */
#ifdef HAVE_OSATOMIC_H
#include <libkern/OSAtomic.h>
#endif /* HAVE_OSATOMIC_H */
static inline void memory_barrier(void)
/* prevent instruction reordering across any call to this function */
{
#ifdef __COVERITY__
/* do nothing */
#elif defined(__cplusplus)
/* we are C++ */
#if __cplusplus >= 201103L
/* C++11 and later has atomics, earlier do not */
std::atomic_thread_fence(std::memory_order_seq_cst);
#endif
#elif defined HAVE_STDATOMIC_H
/* we are C and atomics are in C98 and newer */
atomic_thread_fence(memory_order_seq_cst);
#elif defined(HAVE_OSATOMIC_H)
/* do it the OS X way */
OSMemoryBarrier();
#elif defined(__GNUC__)
asm volatile ("" : : : "memory");
#endif
}
#endif /* _GPSD_COMPILER_H_ */
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