------- Additional Comments From dnovillo at redhat dot com 2005-06-09 19:57 ------- Subject: Re: GCC should combine adjacent stdio calls
On Thu, Jun 09, 2005 at 07:52:42PM -0000, joseph at codesourcery dot com wrote: > Suppose an implementation defines e.g. clearerr as a macro, and the > expansion of that macro just clears bits in the stdio structure and > doesn't call any functions. Then though the user's source code looks like > it contains a function call, after preprocessing it contains manipulation > of bits of the FILE structure for stdout instead. > Ah, OK. In which case, we should reset the "previous builtin" if we find a store to global memory in between. That'd be easy. > (a) It could be stdio's buffer (via setvbuf). > > (b) It could be a glibc memory stream opened with fmemopen (if the user > assigned to stdout - which glibc allows - or you do this optimization on > fprintf and not just printf). > > (c) It could point to a memory mapping of the file being written. > Gah, so we'll need to parse the format string then. Oh, well. Diego. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21982
