PetscUnreachable

Indicate to the compiler that a code-path is logically unreachable

Synopsis

#include <petscmacros.h>
void PetscUnreachable(void)

Note

Indicates to the compiler (usually via some built-in) that a particular code path is always unreachable. Behavior is undefined if this function is ever executed, the user can expect an unceremonious crash.

Example usage

Useful in situations such as switches over enums where not all enumeration values are explicitly covered by the switch

  typedef enum {RED, GREEN, BLUE} Color;

  int foo(Color c)
  {
    // it is known to programmer (or checked previously) that c is either RED or GREEN
    // but compiler may not be able to deduce this and/or emit spurious warnings
    switch (c) {
      case RED:
        return bar();
      case GREEN:
        return baz();
      default:
        PetscUnreachable(); // program is ill-formed if executed
    }
  }

See Also

SETERRABORT(), PETSCABORT(), PETSC_ATTRIBUTE_COLD, PetscAssume()

Level

advanced

Location

include/petscmacros.h

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