#include <stdio.h>
#include <unistd.h>
int main ()
{
Char castdoutline[1024];//A line of information in the standard output of the PS command
char* pctmp = NULL; Points to a string after splitting with a space
Char caselfpid[10]; Self-process PID string
Char capscmd[24]; "PS aux | grep PID "command string
memset (caselfpid, 0, sizeof (caselfpid));
sprintf (Caselfpid,
"%d",
getpid ());
memset (capscmd, 0, sizeof (capscmd));
sprintf (Capscmd,
"PS aux | grep%d ",
getpid ());
Do
//non-loop, just to facilitate control of branch level, easy to control branch flow
{
//By creating a pipeline, call fork to produce a child process,
//execute a Shell to run a command to open a process.
//This process must be closed by the Pclose () function.
file* fp = Popen (Capscmd,//A pointer to a NULL-terminated shell command string,
//This line of command will be uploaded to Bin/sh and use the-C flag,
//Then the shell will execute this command to read from this string.
"R"); Standard output of a file pointer connected to a shell command
if (NULL = = fp)
{
printf ("Call Popen is failed\n");Break
;
}
memset (castdoutline, 0, sizeof (castdoutline));
while (NULL! = fgets (Castdoutline,
sizeof (castdoutline),
FP))
{
//split string with space separator
pctmp = strtok (Castdoutline, "");
//user name skipped, direct matching PID, mismatched skip
pctmp = strtok (NULL, "");
if (0! = strncasecmp (Caselfpid,
Pctmp,
strlen (caselfpid)))
{
continue;
}
//read out process itself CPU usage
pctmp = strtok (NULL, "");
printf ("CPU =%s%%\n", pctmp);
//read out process self MEM occupancy rate
pctmp = strtok (NULL, "");
printf ("MEM =%s%%\n", pctmp);
Break
;
}
//Close the standard I/O stream, wait for the command to finish, and return to the Shell's terminating state.
//If the shell cannot be executed,
//The terminating state returned by Pclose () is the same as the shell has executed exit.
Pclose (FP);
}while (0);
}
$ gcc main.c-o test
$./testCPU = 1.0%MEM = 0.0
$ ps auxuser PID%cpu%MEM VSZ RSS TTY STAT START time COMMANDNSC 24505 1.0 0.0 2004 232 pts /0 s+ 09:46 0:00./test Turn from: http://blog.sina.com.cn/s/blog_4c451e0e0101cmrq.html
Using pipelines to perform PS aux under Linux | grep process ID to get CPU and memory usage
