Programming

Hi all,

I tried to output memory usage information while the process is
executing at a particular time. I found out some people
suggesting calling the ioctl. I followed it and wrote a test example:

#include <unistd.h>
#include <stdlib.h>
#include <iostream.h>
#include <fcntl.h>
#include <sys/procfs.h>

int main(int * argc, char ** argv)
{
pid_t pid = getpid();
char fname[100];
sprintf(fname, "/proc/%ld", pid);
int fd;
fd=open(fname, O_RDONLY);
prpsinfo_t ps_info;

ioctl(fd, PIOCPSINFO, &ps_info);

cout << "pid:" << pid << " init memory:" << ps_info.pr_bysize << endl;

char ** pString;

//char * pInteger[128];
pString = new char * [128];

for(int k = 0; k < 128 ; k++)
{
char *p = new char [1024 * 1024];

pString[k] = p;

}

ioctl(fd, PIOCPSINFO, &ps_info);

cout << "pid:" << pid << " after memory:" << ps_info.pr_bysize <<
endl;

close(fd);

for(int k = 0; k < 128; k++)
delete [](pString[k]);

delete []pString;

}

And compiled it with Sun CC on solaris5.8. I thought the second output
must be more than 128M. But the real one is : memory:0. Have I misused
ioctl or something else?

Best Regards,

Lan Chen

I don't know what you're doing - but getrusage() is the standard way to get cpu usage - usually in ms.

I got:
143> /opt/SUNWspro/bin/CC proc.c -o proc
144> ./proc
pid:15832 init memory:1208320
pid:15832 after memory:135426048

Try opening "/proc/self" which is how everyone else does it. But getting your own pid should work too. Check the error codes after each system call. That will give you a clue.