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Diffstat (limited to 'gcc/doc/extend.texi')
| -rw-r--r-- | gcc/doc/extend.texi | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi index f09338f..02a03ec 100644 --- a/gcc/doc/extend.texi +++ b/gcc/doc/extend.texi @@ -187,6 +187,29 @@ work with C++. (Note that some versions of the GNU C Library contained header files using statement-expression that lead to precisely this bug.) +Jumping into a statement expression with @code{goto} or using a +@code{switch} statement outside the statement expression with a +@code{case} or @code{default} label inside the statement expression is +not permitted. Jumping into a statement expression with a computed +@code{goto} (@pxref{Labels as Values}) yields undefined behavior. +Jumping out of a statement expression is permitted, but if the +statement expression is part of a larger expression then it is +unspecified which other subexpressions of that expression have been +evaluated except where the language definition requires certain +subexpressions to be evaluated before or after the statement +expression. In any case, as with a function call the evaluation of a +statement expression is not interleaved with the evaluation of other +parts of the containing expression. For example, + +@smallexample + foo (), ((@{ bar1 (); goto a; 0; @}) + bar2 ()), baz(); +@end smallexample + +@noindent +will call @code{foo} and @code{bar1} and will not call @code{baz} but +may or may not call @code{bar2}. If @code{bar2} is called, it will be +called after @code{foo} and before @code{bar1} + @node Local Labels @section Locally Declared Labels @cindex local labels |