diff options
Diffstat (limited to 'gcc/doc/extend.texi')
| -rw-r--r-- | gcc/doc/extend.texi | 27 |
1 files changed, 26 insertions, 1 deletions
diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi index de3a1211c73..a4f7a3a68ce 100644 --- a/gcc/doc/extend.texi +++ b/gcc/doc/extend.texi @@ -1803,7 +1803,8 @@ attributes are currently defined for functions on all targets: @code{destructor}, @code{used}, @code{unused}, @code{deprecated}, @code{weak}, @code{malloc}, @code{alias}, @code{warn_unused_result}, @code{nonnull}, @code{gnu_inline}, @code{externally_visible}, -@code{hot}, @code{cold} and @code{artificial}. +@code{hot}, @code{cold}, @code{artificial}, @code{error} +and @code{warning}. Several other attributes are defined for functions on particular target systems. Other attributes, including @code{section} are supported for variables declarations (@pxref{Variable Attributes}) and @@ -1941,6 +1942,30 @@ Whether the function itself is considered for inlining depends on its size and the current inlining parameters. The @code{flatten} attribute only works reliably in unit-at-a-time mode. +@item error ("@var{message}") +@cindex @code{error} function attribute +If this attribute is used on a function declaration and a call to such a function +is not eliminated through dead code elimination or other optimizations, an error +which will include @var{message} will be diagnosed. This is useful +for compile time checking, especially together with @code{__builtin_constant_p} +and inline functions where checking the inline function arguments is not +possible through @code{extern char [(condition) ? 1 : -1];} tricks. +While it is possible to leave the function undefined and thus invoke +a link failure, when using this attribute the problem will be diagnosed +earlier and with exact location of the call even in presence of inline +functions or when not emitting debugging information. + +@item warning ("@var{message}") +@cindex @code{warning} function attribute +If this attribute is used on a function declaration and a call to such a function +is not eliminated through dead code elimination or other optimizations, a warning +which will include @var{message} will be diagnosed. This is useful +for compile time checking, especially together with @code{__builtin_constant_p} +and inline functions. While it is possible to define the function with +a message in @code{.gnu.warning*} section, when using this attribute the problem +will be diagnosed earlier and with exact location of the call even in presence +of inline functions or when not emitting debugging information. + @item cdecl @cindex functions that do pop the argument stack on the 386 @opindex mrtd |