diff options
Diffstat (limited to 'gcc/doc/extend.texi')
| -rw-r--r-- | gcc/doc/extend.texi | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi index fe25cd1b066..4c27320f2b9 100644 --- a/gcc/doc/extend.texi +++ b/gcc/doc/extend.texi @@ -1496,7 +1496,7 @@ attributes when making a declaration. This keyword is followed by an attribute specification inside double parentheses. The following attributes are currently defined for functions on all targets: @code{noreturn}, @code{noinline}, @code{always_inline}, -@code{pure}, @code{const}, @code{nothrow}, +@code{pure}, @code{const}, @code{nothrow}, @code{sentinel}, @code{format}, @code{format_arg}, @code{no_instrument_function}, @code{section}, @code{constructor}, @code{destructor}, @code{used}, @code{unused}, @code{deprecated}, @code{weak}, @code{malloc}, @@ -2111,6 +2111,18 @@ attribute is not available on all platforms. If you need to map the entire contents of a module to a particular section, consider using the facilities of the linker instead. +@item sentinel +@cindex @code{sentinel} function attribute +This function attribute ensures that the last parameter in a function +call is an explicit @code{NULL}. The attribute is only valid on +variadic functions. For example the attribute is automatically set for +the built-in functions @code{execl} and @code{execlp} where @code{NULL} +is the marker for argument list termination. A valid @code{NULL} in +this context is defined as zero with any pointer type. If your system +defines the @code{NULL} macro with an integer type then you need to add +an explicit cast. The warnings for missing or incorrect sentinels are +enabled with @option{-Wformat}. + @item short_call See long_call/short_call. |