read2.c

unix高级编程源代码.<<unix高级编程>>

#include	<setjmp.h>
#include	<signal.h>
#include	"ourhdr.h"

static void		sig_alrm(int);
static jmp_buf	env_alrm;

int
main(void)
{
	int		n;
	char	line[MAXLINE];

	if (signal(SIGALRM, sig_alrm) == SIG_ERR)
		err_sys("signal(SIGALRM) error");

	if (setjmp(env_alrm) != 0)
		err_quit("read timeout");

	alarm(10);
	if ( (n = read(STDIN_FILENO, line, MAXLINE)) < 0)
		err_sys("read error");
	alarm(0);

	write(STDOUT_FILENO, line, n);

	exit(0);
}

static void
sig_alrm(int signo)
{
	longjmp(env_alrm, 1);
}