CLOCKGETCPUCLOCKID(3) Linux Programmer's Manual CLOCKGETCPUCLOCKID(3)

NAME
       clockgetcpuclockid - obtain ID of a process CPU-time clock

SYNOPSIS
       #include 

       int clockgetcpuclockid(pidt pid, clockidt *clockid);

       Link with -lrt (only for glibc versions before 2.17).

   Feature Test Macro Requirements for glibc (see featuretestmacros(7)):

       clockgetcpuclockid():
           XOPENSOURCE >= 600 || POSIXCSOURCE >= 200112L

DESCRIPTION
       The clockgetcpuclockid() function obtains the ID of the CPU-time clock
       of the process whose ID is pid, and returns it in the location  pointed
       to  by  clockid.   If  pid  is zero, then the clock ID of the CPU-time
       clock of the calling process is returned.

RETURN VALUE
       On success, clockgetcpuclockid() returns 0; on error, it  returns  one
       of the positive error numbers listed in ERRORS.

ERRORS
       ENOSYS The  kernel  does not support obtaining the per-process CPU-time
              clock of another process, and pid does not specify  the  calling
              process.

       EPERM  The caller does not have permission to access the CPU-time clock
              of the process specified by  pid.   (Specified  as  an  optional
              error in POSIX.1-2001; does not occur on Linux unless the kernel
              does not support obtaining the  per-process  CPU-time  clock  of
              another process.)

       ESRCH  There is no process with the ID pid.

VERSIONS
       The  clockgetcpuclockid() function is available in glibc since version
       2.2.

ATTRIBUTES
       For  an  explanation  of  the  terms  used   in   this   section,   see
       attributes(7).

       ┌──────────────────────┬───────────────┬─────────┐
       │Interface             │ Attribute     │ Value   │
       ├──────────────────────┼───────────────┼─────────┤
       │clockgetcpuclockid() │ Thread safety │ MT-Safe │
       └──────────────────────┴───────────────┴─────────┘
CONFORMING TO
       POSIX.1-2001.

NOTES
       Calling  clockgettime(2)  with  the  clock  ID  obtained  by a call to
       clockgetcpuclockid() with a pid of 0, is the same as using  the  clock
       ID CLOCKPROCESSCPUTIMEID.

EXAMPLE
       The  example program below obtains the CPU-time clock ID of the process
       whose ID is given on the command line, and then  uses  clockgettime(2)
       to obtain the time on that clock.  An example run is the following:

           $ ./a.out 1                 # Show CPU clock of init process
           CPU-time clock for PID 1 is 2.213466748 seconds

   Program source

       #define XOPENSOURCE 600
       #include 
       #include 
       #include 
       #include 

       int
       main(int argc, char *argv[])
       {
           clockidt clockid;
           struct timespec ts;

           if (argc != 2) {
               fprintf(stderr, "%s \n", argv[0]);
                                             exit(EXITFAILURE);
           }

           if (clockgetcpuclockid(atoi(argv[1]), &clockid) != 0) {
                                             perror("clockgetcpuclockid");
                                             exit(EXITFAILURE);
           }

           if (clockgettime(clockid, &ts) == -1) {
                                             perror("clockgettime");
                                             exit(EXITFAILURE);
           }

           printf("CPU-time clock for PID %s is %ld.%09ld seconds\n",
                                                 argv[1], (long) ts.tvsec, (long) ts.tvnsec);
           exit(EXITSUCCESS);
       }

SEE ALSO
       clockgetres(2), timercreate(2), pthreadgetcpuclockid(3), time(7)

COLOPHON
       This  page  is  part of release 3.53 of the Linux man-pages project.  A
       description of the project, and information about reporting  bugs,  can
       be found at http://www.kernel.org/doc/man-pages/.



Linux                             2013-07-04            CLOCKGETCPUCLOCKID(3)