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setjmp

int setjmp( jmp_buf env );

Description

Store the PC (program counter), SP (stack pointer) and other information about the current state into env. The saved information can be restored by executing longjmp().

NOTE	you cannot use setjmp() to move out of slice statements, costatements, or cofunctions.

Typical usage:

   

switch (setjmp(e)) {
   case 0:           // first time
      f();           // try to execute f(), may call longjmp()
      break;         // if we get here, f() was successful
   case 1:           // to get here, f() called longjmp()
      /* do exception handling */
      break;
   case 2:           // similar to above, but different exception code
     ...
}
f() {
   g()
   ...
}
g() {
   ...
   longjmp(e,2);    // exception code 2, jump to setjmp() statement,
                    // setjmp() returns 2, so execute
                    // case 2 in the switch statement
}

Parameters

env

Information about the current state

Return value

Returns zero if it is executed. After longjmp() is executed, the program counter, stack pointer and etc. are restored to the state when setjmp() was executed the first time. However, this time setjmp() returns whatever value is specified by the longjmp() statement.

Library

SYS.LIB

See also

longjmp