I'm looking at the #include guards in various .h files in /usr/include. There seem to be different (comment) idioms present at the bottom of those files/#include guards.
For example: ctype.h: #endif /* !_CTYPE_H_ */ float.h: #endif /* _FLOAT_H_ */ err.h: #endif /* !_ERR_H_ */ curses.h: #endif /* _CURSES_H_ */ Is there agreement on what notation is correct? It seems to me that both are defensible or at least arguable. The straightforward idiom without the ! works simply as a reminder of which file/#define the #endif belongs to. The version with the ! seems to me to be intended to also take note of the fact that it says #ifndef at the top, with emphasis on the n. >From running commands such as $ grep '#endif /\* _' *.h | wc -l and $ grep '#endif /\* !_' *.h | wc -l it would appear the former is about twice as common. Should a single style be adopted? style(9) doesn't cover this admittedly less-than-crucial point. Speaking of include guards, is #pragma once ever okay here, or is that a big no-no? Thanks and regards, Ian (Ian Ropers)
