__attribute__((unused))

Specifies that the programmer is aware that a variable or function parameter is not referred to.

Syntax

  function-parameter  __attribute__((unused));

  variable-declaration  __attribute__((unused));

  variable-definition  __attribute__((unused));

Remarks

This attribute specifies that the compiler should not issue a warning for an object if the object is not referred to. This attribute specification has no effect if the compiler's unused warning setting is off.

Listing 1. Example of the unused attribute

void f(int a __attribute__((unused))) /* No warning for a. */
{
  int b __attribute__((unused)); /* No warning for b. */
  int c; /* Possible warning for c. */

  return 20;
}