ssignal.c

来自「操作系统SunOS 4.1.3版本的源码」· C语言 代码 · 共 67 行

#if !defined(lint) && defined(SCCSIDS)
static	char sccsid[] = "@(#)ssignal.c 1.1 92/07/30 SMI"; /* from S5R2 1.2 */
#endif

/*LINTLIBRARY*/
/*
 *	ssignal, gsignal: software signals
 */
#include <signal.h>

/* Highest allowable user signal number */
#define MAXSIG NSIG

/* Lowest allowable signal number (lowest user number is always 1) */
#define MINSIG (-4)

/* Table of signal values */
typedef int (*sigfunc)();
sigfunc *ssigp;
	

sigfunc *
_ssig()
{
	if (ssigp == 0)
		ssigp = (sigfunc *)calloc(MAXSIG-MINSIG+1, sizeof (sigfunc));
	return (ssigp);
}

int
(*ssignal(sig, fn))()
register int sig, (*fn)();
{
	register int (*savefn)();
	register sigfunc *sp = _ssig();

	if (sp == 0)
		return (SIG_DFL);
	if(sig >= MINSIG && sig <= MAXSIG) {
		savefn = sp[sig-MINSIG];
		sp[sig-MINSIG] = fn;
	} else
		savefn = SIG_DFL;

	return(savefn);
}

int
gsignal(sig)
register int sig;
{
	register int (*sigfn)();
	register sigfunc *sp = _ssig();

	if (sp == 0)
		return (0);
	if(sig < MINSIG || sig > MAXSIG ||
				(sigfn = sp[sig-MINSIG]) == SIG_DFL)
		return(0);
	else if(sigfn == SIG_IGN)
		return(1);
	else {
		sp[sig-MINSIG] = SIG_DFL;
		return((*sigfn)(sig));
	}
}