Unix/Linux下 getrusage 的用法

#include <sys/resource>
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；