Improve portability of getopt reset #1545
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Avoid duplication across multiple files by defining a symbol USE_BUNDLED_GETOPT in configure.py, and clean up the resulting #include directives.
getopt reset is done sometimes with "optind = 0", sometimes with "optind = 1". Unfortunately, neither is portable. For example, if the bundled getopt see "optind = 1" on the very first call it will implicitly add a dash in front of the first argument; and while some glibc versions even crashed if reset with "optind = 1", Apple's getopt did the same for "optind = 0". Since we know that there will always be two getopt calls only, of which the first will be in ReadFlags, place the ugly code there so that it is not replicated all over ninja.cc. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Why not use the bundled getopt all the time? |
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That would be a questioni for you. :-) There could be prototype compatibility issues I guess, similar to AIX. |
I didn't write any of this, so I have no idea.
You mean that the definition of getopt might conflict with the system provided one? |
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Yes, for example const differences could be a problem. |
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I don't quite remember, but I think I first wrote the code assuming that getopt was always available, then once we were on a system that didn't have it we added the builtin one. I agree that maybe always using the builtin one is a good idea. |
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Always using the builtin one is the way to go IMHO. Eventually even move on to a different solution with a better API (to make stuff like #1546 easier). |
getopt reset is done sometimes with "optind = 0", sometimes with "optind = 1". Unfortunately, neither is portable. For example, if the bundled getopt see "optind = 1" on the very first call it will implicitly add a dash in front of the first argument; and while some glibc versions even had reports of crashes if reset with "optind = 1", Apple's getopt did the same for "optind = 0".
Since we know that there will always be two getopt calls only, of which the first will be in ReadFlags, place the ugly code there so that it is not replicated all over ninja.cc.