在这个部分，我们将看到C语言中的setjump和longjump是什么。setjump()和longjump()位于setjmp.h库中。这两个函数的语法如下所示。

setjump(jmp_buf buf) : uses buf to store current position and returns 0.
longjump(jmp_buf buf, i) : Go back to place pointed by buf and return i.

These are used in C for exception handling. The setjump() can be used as try block, and longjump() can be used as throw statement. The longjump() transfers control the pointe which is pointed by setjump().

Here we will see how to print a number 100 times without using recursion, loop, or macro expansion. Here we will use the setjump() and longjump() functions to do that.

Example

#include <stdio.h>
#include <setjmp.h>
jmp_buf buf;
main() {
   int x = 1;
   setjmp(buf); //set the jump position using buf
   printf("5"); // Prints a number
   x++;
   if (x <= 100)
      longjmp(buf, 1); // Jump to the point located by setjmp
}

输出

5555555555555555555555555555555555555555555555555555555555555555555555555555
555555555555555555555555