getrusage 的用法

getrlimit/setrlimit, getusage

#include
int getrusage(int who, struct rusage *r_usage);

利用getrusage可以得到进程的相关资源信息。如：用户开销时间，系统开销时间，接收的信号量等等;

下面是rusage的结构：
struct rusage {
       struct timeval ru_utime; /* user time used */
       struct timeval ru_stime; /* system time used */
       long ru_maxrss;
      #define ru_first ru_ixrss
       long ru_ixrss;  /* XXX: 0 */
       long ru_idrss;  /* XXX: sum of rm_asrss */
       long ru_isrss;  /* XXX: 0 */
       long ru_minflt;  /* any page faults not requiring I/O */
      long ru_majflt;  /* any page faults requiring I/O */
       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 " */
      #define ru_last  ru_nivcsw
      };
如果参数who是RUSAGE_SELF，则得到的是当前进程的资源信息。如果是RUSAGE_CHILDREN，则将返回当进程的终止掉的子进程和等待子进程的资源信息。当调用成功后，返回0，否则-1；
下面是一个例子：

int who = RUSAGE_SELF;
struct rusage usage;
int ret;

ret = getrusage(who, &usage);

这样你就可以用usage获取你想要的东西了；