goto statement

Transfers control unconditionally to the desired location.

Used when it is otherwise impossible to transfer control to the desired location using conventional constructs.

Syntax

Explanation

The goto statement causes an unconditional jump (transfer of control) to the statement prefixed by the named label (which must appear in the same function as the goto statement) , except when this jump would enter the scope of a variable-length array or another variably-modified type. (since C99)

A label is an identifier followed by a colon (:)and a statement(until C23). Labels are the only identifiers that have function scope

goto lab1; // OK: going into the scope of a regular variable
    int n = 5;
lab1:; // Note, n is uninitialized, as if declared by int n;
 
//   goto lab2;   // Error: going into the scope of two VM types
     double a[n]; // a VLA
     int (*p)[n]; // a VM pointer
lab2:

{
   int n = 1;
label:;
   int a[n]; // re-allocated 10 times, each with a different size
   if (n++ < 10) goto label; // leaving the scope of a VM
}

Keywords

goto

Notes

C++ imposes additional limitations on the goto statement, but allows labels before declarations (which are statements in C++).

Example

#include <stdio.h>
 
int main(void)
{
    // goto can be used to leave a multi-level loop easily
    for (int x = 0; x < 3; x++) {
        for (int y = 0; y < 3; y++) {
            printf("(%d;%d)\n",x,y);
            if (x + y >= 3) goto endloop;
        }
    }
endloop:;
}

(0;0)
(0;1)
(0;2)
(1;0)
(1;1)
(1;2)

References

See also