C library function - longjmp()

Description

The C library function void longjmp(jmp_buf environment, int value) restores the environment saved by the most recent call to setjmp() macro in the same invocation of the program with the corresponding jmp_buf argument.

Declaration

Following is the declaration for longjmp() function.

void longjmp(jmp_buf environment, int value)

Parameters

• environment -- This is the object of type jmp_buf containing information to restore the environment at the setjmp's calling point.

• value -- This is the value to which the setjmp expression evaluates.

Return Value

This function does not return any value.

Example

The following example shows the usage of longjmp() function.

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

int main()
{
   int val;
   jmp_buf env_buffer;

   /* save calling environment for longjmp */
   val = setjmp( env_buffer );
   if( val != 0 ) 
   {
      printf("Returned from a longjmp() with value = %s\n", val);
      exit(0);
   }
   printf("Jump function call\n");
   jmpfunction( env_buffer );
   
   return(0);
}

void jmpfunction(jmp_buf env_buf)
{
   longjmp(env_buf, "tutorialspoint.com");
}

Let us compile and run the above program, this will produce the following result:

Jump function call
Returned from a longjmp() with value = tutorialspoint.com