src/port/pgstrsignal.c

   1 /*-------------------------------------------------------------------------
   2  *
   3  * pgstrsignal.c
   4  *        Identify a Unix signal number
   5  *
   6  * On platforms compliant with modern POSIX, this just wraps strsignal(3).
   7  * Elsewhere, we do the best we can.
   8  *
   9  * This file is not currently built in MSVC builds, since it's useless
  10  * on non-Unix platforms.
  11  *
  12  * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
  13  * Portions Copyright (c) 1994, Regents of the University of California
  14  *
  15  * IDENTIFICATION
  16  *        src/port/pgstrsignal.c
  17  *
  18  *-------------------------------------------------------------------------
  19  */
  20
  21 #include "c.h"
  22
  23
  24 /*
  25  * pg_strsignal
  26  *
  27  * Return a string identifying the given Unix signal number.
  28  *
  29  * The result is declared "const char *" because callers should not
  30  * modify the string.  Note, however, that POSIX does not promise that
  31  * the string will remain valid across later calls to strsignal().
  32  *
  33  * This version guarantees to return a non-NULL pointer, although
  34  * some platforms' versions of strsignal() reputedly do not.
  35  *
  36  * Note that the fallback cases just return constant strings such as
  37  * "unrecognized signal".  Project style is for callers to print the
  38  * numeric signal value along with the result of this function, so
  39  * there's no need to work harder than that.
  40  */
  41 const char *
  42 pg_strsignal(int signum)
  43 {
  44         const char *result;
  45
  46         /*
  47          * If we have strsignal(3), use that --- but check its result for NULL.
  48          */
  49 #ifdef HAVE_STRSIGNAL
  50         result = strsignal(signum);
  51         if (result == NULL)
  52                 result = "unrecognized signal";
  53 #else
  54
  55         /*
  56          * We used to have code here to try to use sys_siglist[] if available.
  57          * However, it seems that all platforms with sys_siglist[] have also had
  58          * strsignal() for many years now, so that was just a waste of code.
  59          */
  60         result = "(signal names not available on this platform)";
  61 #endif
  62
  63         return result;
  64 }