21 #ifndef _freetds_macros_h_    22 #define _freetds_macros_h_    24 #ifndef _freetds_config_h_    25 #error should include config.h before    32 #define TDS_ZERO_FREE(x) do {free((x)); (x) = NULL;} while(0)    33 #define TDS_VECTOR_SIZE(x) (sizeof(x)/sizeof(x[0]))    36 #define TDS_OFFSET(type, field) offsetof(type, field)    38 #define TDS_OFFSET(type, field) (((char*)&((type*)0)->field)-((char*)0))    41 #if ENABLE_EXTRA_CHECKS    42 # if defined(__llvm__) || (defined(__GNUC__) && (__GNUC__ >= 5 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 6)))    43 # define TDS_COMPILE_CHECK(name,check) \    44     _Static_assert(check,#name)    45 # elif defined(__GNUC__) && __GNUC__ >= 2    46 # define TDS_COMPILE_CHECK(name,check) \    47     extern int name[(check)?1:-1] __attribute__ ((unused))    49 # define TDS_COMPILE_CHECK(name,check) \    50     extern int name[(check)?1:-1]    52 # define TDS_EXTRA_CHECK(stmt) stmt    54 # define TDS_COMPILE_CHECK(name,check) \    55     extern int disabled_check_##name    56 # define TDS_EXTRA_CHECK(stmt)    59 #if defined(__GNUC__) && __GNUC__ >= 3    60 # define TDS_LIKELY(x)  __builtin_expect(!!(x), 1)    61 # define TDS_UNLIKELY(x)    __builtin_expect(!!(x), 0)    63 # define TDS_LIKELY(x)  (x)    64 # define TDS_UNLIKELY(x)    (x)    67 #if ENABLE_EXTRA_CHECKS && defined(__GNUC__) && __GNUC__ >= 4    68 #define TDS_WUR __attribute__ ((__warn_unused_result__))