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What is the lifetime of temporary function arguments?
When are temporary objects destroyed?
It is said that temporary variables are destroyed as the last step in evaluating the full-expression, e.g.
bar( foo().c_str() );
temporary pointer lives until bar returns, but what for the
baz( bar( foo().c_str() ) );
is it still lives until bar returns, or baz return means full-expression end here, compilers I checked destruct objects after baz returns, but can I rely on that?
Temporaries live until the end of the full expression in which they are created. A "full expression" is an expression that's not a sub-expression of another expression.
In baz(bar(...));, bar(...) is a subexpression of baz(...), while baz(...) is not a subexpression of anything. Therefore, baz(...) is the full expression, and all temporaries created during the evaluation of this expression will not be deleted until after baz(...) returned.