引言:在编写程序时,经常在函数内部使用goto语句来跳转,从而进行出错处理,那么如果想要在函数之间进行跳转该怎么做呢?使用setjmp和longjmp函数。
给出示例程序:
#include <stdio.h> #include <stdlib.h> #include <setjmp.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 int volaval; static int statval; globval = 1; autoval = 2; regival = 3; volaval = 4; statval = 5; if(setjmp(jmpbuffer) != 0){ printf("after longjmp:\n"); printf("global = %d, autoval = %d, regival = %d, volaval = %d, statval = %d\n", globval, autoval, regival, volaval, statval); exit(0); } /* * Change variable after setjmp, buf before longjmp. */ globval = 95; autoval = 96; regival = 97; volaval = 98; statval = 99; f1(autoval, regival, volaval, statval);/*never returns*/ exit(0); } static void f1(int i, int j, int k, int l) { printf("in f1():\n"); printf("global = %d, autoval = %d, regival = %d, volaval = %d, statval = %d\n", globval,i, j, k, l); f2(); } static void f2(void) { longjmp(jmpbuffer, 1); }
in f1(): global = 95, autoval = 96, regival = 97, volaval = 98, statval = 99 after longjmp: global = 95, autoval = 96, regival = 97, volaval = 98, statval = 99