Get total system memory without external tools

Question

To get total installed RAM I can use popen("sysctl -n hw.memsize", "r"), but is there some library to get this info without running external tools?

Answer 1

sysctl

You can use sysctl (more detail here)

The symbols used in this section are declared in the file sysctl.h. — Function:

int sysctl (int *names, int nlen, void *oldval, size_t *oldlenp, void *newval, size_t newlen)

getrusage

getrusage

#include <sys/resource.h> 

int getrusage(int who, struct rusage *usage); 

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 */
};

Answer 2

See also here:

http://www.cocoadev.com/index.pl?HowToGetHardwareAndNetworkInfo

Answer 3

You can use the api getrusage

     int who = RUSAGE_SELF;
    struct rusage usage={0,};
    int ret=0;
    ret = getrusage(who, &usage);

Look up the structure of rusage and pick the values of concern to you.