Date: Thu, 27 Feb 1997 15:21:55 +1100 From: Bruce Evans <bde@zeta.org.au> To: freebsd-hackers@freefall.freebsd.org, mpp@freefall.freebsd.org Subject: Re: sig*set macros in <signal.h> Message-ID: <199702270421.PAA13463@godzilla.zeta.org.au>
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>Is there a good reason for having the sig*set macros defined >in <signal.h> and the equivalent functions in libc? Yes. ANSI requires function versions for almost all function-like interfaces, so that applications can use the function version if necessary (*). sig*set are POSIX functions, not ANSI. I'm not sure if POSIX has the same rule, but it's a good rule. (*) The function version is necessary for calls through a function pointer. For the few function-like interfaces that may have side effects on their args, the function version is necessary for avoiding side effects. >The macros >are only defined if _ANSI_SOURCE isn't. Neither are prototypes for the sig*set functions declared. This is because they aren't ANSI functions. >Plus it doesn't looks like >they are used that much anyways (about 2 dozen programs). This is because most programs in /usr/src that use signals assume BSD signal semantics, so they can get away with using signal() instead of sigaction(). Bruce
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