Date: Sun, 18 Apr 2010 18:23:11 +0000 (UTC) From: Konstantin Belousov <kib@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r206802 - head/lib/libc/sys Message-ID: <201004181823.o3IINBKB056640@svn.freebsd.org>
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Author: kib Date: Sun Apr 18 18:23:11 2010 New Revision: 206802 URL: http://svn.freebsd.org/changeset/base/206802 Log: Revert r206649. Simplify the presented declaration of struct sigaction, noting the caveat in the text. Real layout of the structure and exposed implementation namespace only obfuscates the usage. Submitted by: bde MFC after: 3 days Modified: head/lib/libc/sys/sigaction.2 Modified: head/lib/libc/sys/sigaction.2 ============================================================================== --- head/lib/libc/sys/sigaction.2 Sun Apr 18 17:50:09 2010 (r206801) +++ head/lib/libc/sys/sigaction.2 Sun Apr 18 18:23:11 2010 (r206802) @@ -28,7 +28,7 @@ .\" From: @(#)sigaction.2 8.2 (Berkeley) 4/3/94 .\" $FreeBSD$ .\" -.Dd April 13, 2010 +.Dd April 18, 2010 .Dt SIGACTION 2 .Os .Sh NAME @@ -40,16 +40,11 @@ .In signal.h .Bd -literal struct sigaction { - union { - void (*__sa_handler)(int); - void (*__sa_sigaction)(int, siginfo_t *, void *); - } __sigaction_u; /* signal handler */ + void (*sa_handler)(int); + void (*sa_sigaction)(int, siginfo_t *, void *); int sa_flags; /* see signal options below */ sigset_t sa_mask; /* signal mask to apply */ }; - -#define sa_handler __sigaction_u.__sa_handler -#define sa_sigaction __sigaction_u.__sa_sigaction .Ed .Ft int .Fo sigaction @@ -148,6 +143,16 @@ If is non-zero, the previous handling information for the signal is returned to the user. .Pp +The above declaration of +.Vt "struct sigaction" +is not literal. +It is provided only to list the accessible members. +See +.In sys/signal.h +for the actual definition. +In particular, the storage occupied by sa_handler and sa_sigaction overlaps, +and an application can not use both simultaneously. +.Pp Once a signal handler is installed, it normally remains installed until another .Fn sigaction @@ -496,16 +501,6 @@ or .Dv SIG_IGN this way. .Pp -If preprocessing symbol -.Va _POSIX_C_SOURCE -with the value >= 199309 is not defined, the following declaration for -the handler shall be used: -.Bl -tag -offset indent -width short -.It Tn POSIX Dv SA_SIGINFO : -.Ft void -.Fn handler int "struct __sigaction *" "void *" ; -.El -.Pp If the .Dv SA_SIGINFO flag is not set, the handler function should match
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