/*-------------------------------------------------------------------------

 *

 * pgstrsignal.c

 *    Identify a Unix signal number

 *

 * On platforms compliant with modern POSIX, this just wraps strsignal(3).

 * Elsewhere, we do the best we can.

 *

 * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group

 * Portions Copyright (c) 1994, Regents of the University of California

 *

 * IDENTIFICATION

 *    src/port/pgstrsignal.c

 *

 *-------------------------------------------------------------------------

 */

#include "c.h"

/*

 * pg_strsignal

 *

 * Return a string identifying the given Unix signal number.

 *

 * The result is declared "const char *" because callers should not

 * modify the string.  Note, however, that POSIX does not promise that

 * the string will remain valid across later calls to strsignal().

 *

 * This version guarantees to return a non-NULL pointer, although

 * some platforms' versions of strsignal() reputedly do not.

 *

 * Note that the fallback cases just return constant strings such as

 * "unrecognized signal".  Project style is for callers to print the

 * numeric signal value along with the result of this function, so

 * there's no need to work harder than that.

 */

const char *

pg_strsignal(int signum)

{

  const char *result;

  /*

   * If we have strsignal(3), use that --- but check its result for NULL.

   */

#ifdef HAVE_STRSIGNAL

  result = strsignal(signum);

  if (result == NULL)

    result = "unrecognized signal";

#else

  /*

   * We used to have code here to try to use sys_siglist[] if available.

   * However, it seems that all platforms with sys_siglist[] have also had

   * strsignal() for many years now, so that was just a waste of code.

   */

  result = "(signal names not available on this platform)";

#endif

  return result;

}