diff options
Diffstat (limited to 'gcc/doc')
| -rw-r--r-- | gcc/doc/extend.texi | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi index e290265..267fccd 100644 --- a/gcc/doc/extend.texi +++ b/gcc/doc/extend.texi @@ -42,6 +42,8 @@ extensions, accepted by GCC in C90 mode and in C++. * Named Address Spaces::Named address spaces. * Zero Length:: Zero-length arrays. * Empty Structures:: Structures with no members. +* Flexible Array Members in Unions:: Unions with Flexible Array Members. +* Flexible Array Members alone in Structures:: Structures with only Flexible Array Members. * Variable Length:: Arrays whose length is computed at run time. * Variadic Macros:: Macros with a variable number of arguments. * Escaped Newlines:: Slightly looser rules for escaped newlines. @@ -1873,6 +1875,38 @@ The structure has size zero. In C++, empty structures are part of the language. G++ treats empty structures as if they had a single member of type @code{char}. +@node Flexible Array Members in Unions +@section Unions with Flexible Array Members +@cindex unions with flexible array members +@cindex unions with FAMs + +GCC permits a C99 flexible array member (FAM) to be in a union: + +@smallexample +union with_fam @{ + int a; + int b[]; +@}; +@end smallexample + +If every member of a union is a flexible array member, the size of +such a union is zero. + +@node Flexible Array Members alone in Structures +@section Structures with only Flexible Array Members +@cindex structures with only flexible array members +@cindex structures with only FAMs + +GCC permits a C99 flexible array member (FAM) to be alone in a structure: + +@smallexample +struct only_fam @{ + int b[]; +@}; +@end smallexample + +The size of such a structure is zero. + @node Variable Length @section Arrays of Variable Length @cindex variable-length arrays |