diff options
Diffstat (limited to 'absl/base/attributes.h')
| -rw-r--r-- | absl/base/attributes.h | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/absl/base/attributes.h b/absl/base/attributes.h index faa5b27e..cf2cb550 100644 --- a/absl/base/attributes.h +++ b/absl/base/attributes.h @@ -678,4 +678,25 @@ #define ABSL_CONST_INIT #endif // ABSL_HAVE_CPP_ATTRIBUTE(clang::require_constant_initialization) +// ABSL_ATTRIBUTE_PURE_FUNCTION +// +// ABSL_ATTRIBUTE_PURE_FUNCTION is used to annotate declarations of "pure" +// functions. A function is pure if its return value is only a function of its +// arguments. The pure attribute prohibits a function from modifying the state +// of the program that is observable by means other than inspecting the +// function's return value. Declaring such functions with the pure attribute +// allows the compiler to avoid emitting some calls in repeated invocations of +// the function with the same argument values. +// +// Example: +// +// ABSL_ATTRIBUTE_PURE_FUNCTION int64_t ToInt64Milliseconds(Duration d); +#if ABSL_HAVE_CPP_ATTRIBUTE(gnu::pure) +#define ABSL_ATTRIBUTE_PURE_FUNCTION [[gnu::pure]] +#elif ABSL_HAVE_ATTRIBUTE(pure) +#define ABSL_ATTRIBUTE_PURE_FUNCTION __attribute__((pure)) +#else +#define ABSL_ATTRIBUTE_PURE_FUNCTION +#endif + #endif // ABSL_BASE_ATTRIBUTES_H_ |