获取进程使用的资源，getrusage

GETRUSAGE(2)                                    Linux Programmer's Manual                                    GETRUSAGE(2)
 
NAME
       getrusage - get resource usage
 
SYNOPSIS
       #include
       #include
 
       int getrusage(int who, struct rusage *usage);
 
DESCRIPTION
       getrusage()  returns current resource usages, for a who of either RUSAGE_SELF or RUSAGE_CHILDREN.  The former asks
       for resources used by the calling process, the latter for resources used by those of its children that have termi-
       nated and have been waited for.
 
           struct rusage {
               struct timeval ru_utime; /* user time used */
               struct timeval ru_stime; /* system time used */
               long   ru_maxrss;        /* maximum resident set size */
               long   ru_ixrss;         /* integral shared memory size */
               long   ru_idrss;         /* integral unshared data size */
               long   ru_isrss;         /* integral unshared stack size */
               long   ru_minflt;        /* page reclaims */
               long   ru_majflt;        /* page faults */
               long   ru_nswap;         /* swaps */
               long   ru_inblock;       /* block input operations */
               long   ru_oublock;       /* block output operations */
               long   ru_msgsnd;        /* messages sent */
               long   ru_msgrcv;        /* messages received */
               long   ru_nsignals;      /* signals received */
               long   ru_nvcsw;         /* voluntary context switches */

               long   ru_nivcsw;        /* involuntary context switches */
           };
 
RETURN VALUE
       On success, zero is returned.  On error, -1 is returned, and errno is set appropriately.
 
ERRORS
       EFAULT usage points outside the accessible address space.
 
       EINVAL who is invalid.
 
CONFORMING TO
       SVr4, 4.3BSD.  POSIX.1-2001 specifies getrusage(), but only specifies the fields ru_utime and ru_stime.
 
NOTES
       Including  is not required these days, but increases portability.  (Indeed, struct timeval is defined
       in .)
 
       In Linux kernel versions before 2.6.9, if the disposition of SIGCHLD is set to SIG_IGN then the resource usages of
       child processes are automatically included in the value returned by RUSAGE_CHILDREN, although POSIX.1-2001 explic-
       itly prohibits this.  This non-conformance is rectified in Linux 2.6.9 and later.
 
       The above struct was taken from 4.3BSD Reno.  Not all fields are meaningful under Linux.  In linux  2.4  only  the
       fields  ru_utime,  ru_stime, ru_minflt, and ru_majflt are maintained.  Since Linux 2.6, ru_nvcsw and ru_nivcsw are
       also maintained.
 
SEE ALSO
       getrlimit(2), times(2), wait(2), wait4(2)
 
COLOPHON
       This page is part of release 2.77 of the Linux man-pages project.  A description of the project,  and  information
       about reporting bugs, can be found at .
 
Linux                                                   2004-11-16                                           GETRUSAGE(2)