带优化和不带优化的setjmp 和longjmp函数

#include <setjmp.h>
#include <stdio.h>
#include <stdlib.h>

static void f1( int, int, int, int );
static void f2(void);

static jmp_buf	jmpbuffer;
static int	globval;

int main(void)
{
	int		autoval;
	register int	regival;
	volatile	volaval;
	static	int	statval;


	globval = 1; autoval = 2; regival = 3; volaval = 4; statval =5;
//使用了ISO C字符串的自动连接
	if( setjmp( jmpbuffer ) != 0 ){
		printf( "after longjmp:\n" );
		printf( "globval = %d, autoval = %d, "
			"regival = %d, volaval = %d, statval = %d\n ",
			globval, autoval, regival, volaval,statval );

		exit(0);
	}
	
	globval = 95; autoval = 96; regival = 97; volaval = 98; statval = 99;
	
	f1( autoval, regival, volaval, statval );
	exit( 0 );	
}

void f1( int i, int j, int k, int l )
{
	printf( "in fl!\n" );
	printf( "globval = %d, autoval = %d, regival = %d, volaval = %d, statval = %d\n ",globval, i, j, k, l );
	f2();	
}

void f2()
{
	printf( "in f2!\n" );
	longjmp( jmpbuffer, 1 );
}

不进行优化的运行结果如下：

 wangkai@ubuntu:~/Test$ cc getuid.c 
wangkai@ubuntu:~/Test$ ./a.out 
in fl!
globval = 95, autoval = 96, regival = 97, volaval = 98, statval = 99
 in f2!
after longjmp:
globval = 95, autoval = 96, regival = 97, volaval = 98, statval = 99
 wangkai@ubuntu:~/Test$ 

进行全部优化的编译

wangkai@ubuntu:~/Test$ cc -O getuid.c 
wangkai@ubuntu:~/Test$ ./a.out 
in fl!
globval = 95, autoval = 96, regival = 97, volaval = 98, statval = 99
 in f2!
after longjmp:
globval = 95, autoval = 2, regival = 3, volaval = 98, statval = 99