time/clock_getcpuclockid.c

   1 /* Get a clockid_t for the process CPU clock of a given process.  Generic.
   2    Copyright (C) 2000-2023 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <errno.h>
  20 #include <time.h>
  21 #include <unistd.h>
  22 #include <shlib-compat.h>
  23
  24 int
  25 __clock_getcpuclockid (pid_t pid, clockid_t *clock_id)
  26 {
  27   /* We don't allow any process ID but our own.  */
  28   if (pid != 0 && pid != getpid ())
  29     return EPERM;
  30
  31 #ifdef CLOCK_PROCESS_CPUTIME_ID
  32   /* Store the number.  */
  33   *clock_id = CLOCK_PROCESS_CPUTIME_ID;
  34
  35   return 0;
  36 #else
  37   /* We don't have a timer for that.  */
  38   return ENOENT;
  39 #endif
  40 }
  41 versioned_symbol (libc, __clock_getcpuclockid, clock_getcpuclockid, GLIBC_2_17);
  42 /* clock_getcpuclockid moved to libc in version 2.17;
  43    old binaries may expect the symbol version it had in librt.  */
  44 #if SHLIB_COMPAT (libc, GLIBC_2_2, GLIBC_2_17)
  45 compat_symbol (libc, __clock_getcpuclockid, clock_getcpuclockid, GLIBC_2_2);
  46 #endif