/proc/%d/stat

procstat.h

struct StatStuff
{
    int pid; // %d
    char comm[256]; // %s
    char state; // %c
    int ppid; // %d
    int pgrp; // %d
    int session; // %d
    int tty_nr; // %d
    int tpgid; // %d
    unsigned long flags; // %lu OR %l
    unsigned long minflt; // %lu
    unsigned long cminflt; // %lu
    unsigned long majflt; // %lu
    unsigned long cmajflt; // %lu
    unsigned long utime; // %lu
    unsigned long stime;  // %lu
    long cutime; // %ld
    long cstime; // %ld
    long priority; // %ld
    long nice; // %ld
    long num_threads; // %ld
    long itrealvalue; // %ld
    unsigned long starttime; // %lu
    unsigned long vsize; // %lu
    long rss; // %ld
    unsigned long rlim; // %lu
    unsigned long startcode; // %lu
    unsigned long endcode; // %lu
    unsigned long startstack; // %lu
    unsigned long kstkesp; // %lu
    unsigned long kstkeip; // %lu
    unsigned long signal; // %lu
    unsigned long blocked; // %lu
    unsigned long sigignore; // %lu
    unsigned long sigcatch; // %lu
    unsigned long wchan; // %lu
    unsigned long nswap; // %lu
    unsigned long cnswap; // %lu
    int exit_signal; // %d
    int processor; // %d
    unsigned long rt_priority; // %lu
    unsigned long policy; // %lu
    unsigned long long delayacct_blkio_ticks; // %llu
};

int readStat(pid_t pid, struct StatStuff *s)
{
    static const char * const procfile = "/proc/%d/stat";
    static const char * const format = "%d %s %c %d %d %d %d %d %lu %lu %lu %lu %lu %lu %lu %ld %ld %ld %ld %ld %ld %lu %lu %ld %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %d %d %lu %lu %llu";

    char buf[128];
    sprintf(buf, procfile, pid);

    FILE *proc = fopen(buf, "r");
    if(proc)
    {
        int ret = fscanf(proc, format,
                         &s->pid,
                         s->comm,
                         &s->state,
                         &s->ppid,
                         &s->pgrp,
                         &s->session,
                         &s->tty_nr,
                         &s->tpgid,
                         &s->flags,
                         &s->minflt,
                         &s->cminflt,
                         &s->majflt,
                         &s->cmajflt,
                         &s->utime,
                         &s->stime,
                         &s->cutime,
                         &s->cstime,
                         &s->priority,
                         &s->nice,
                         &s->num_threads,
                         &s->itrealvalue,
                         &s->starttime,
                         &s->vsize,
                         &s->rss,
                         &s->rlim,
                         &s->startcode,
                         &s->endcode,
                         &s->startstack,
                         &s->kstkesp,
                         &s->kstkeip,
                         &s->signal,
                         &s->blocked,
                         &s->sigignore,
                         &s->sigcatch,
                         &s->wchan,
                         &s->nswap,
                         &s->cnswap,
                         &s->exit_signal,
                         &s->processor,
                         &s->rt_priority,
                         &s->policy,
                         &s->delayacct_blkio_ticks);
        fclose(proc);
        if(ret == 42) return 1;
    }
    return 0;
}

void printStat(FILE *out, struct StatStuff *stuff)
{
    fprintf(out,"pid = %d\n", stuff->pid);
    fprintf(out,"comm = %s\n", stuff->comm);
    fprintf(out,"state = %c\n", stuff->state);
    fprintf(out,"ppid = %d\n", stuff->ppid);
    fprintf(out,"pgrp = %d\n", stuff->pgrp);
    fprintf(out,"session = %d\n", stuff->session);
    fprintf(out,"tty_nr = %d\n", stuff->tty_nr);
    fprintf(out,"tpgid = %d\n", stuff->tpgid);
    fprintf(out,"flags = %lu\n", stuff->flags);
    fprintf(out,"minflt = %lu\n", stuff->minflt);
    fprintf(out,"cminflt = %lu\n", stuff->cminflt);
    fprintf(out,"majflt = %lu\n", stuff->majflt);
    fprintf(out,"cmajflt = %lu\n", stuff->cmajflt);
    fprintf(out,"utime = %lu\n", stuff->utime);
    fprintf(out,"stime = %lu\n", stuff->stime);
    fprintf(out,"cutime = %ld\n", stuff->cutime);
    fprintf(out,"cstime = %ld\n", stuff->cstime);
    fprintf(out,"priority = %ld\n", stuff->priority);
    fprintf(out,"nice = %ld\n", stuff->nice);
    fprintf(out,"num_threads = %ld\n", stuff->num_threads);
    fprintf(out,"itrealvalue = %ld\n", stuff->itrealvalue);
    fprintf(out,"starttime = %lu\n", stuff->starttime);
    fprintf(out,"vsize = %lu\n", stuff->vsize);
    fprintf(out,"rss = %ld\n", stuff->rss);
    fprintf(out,"rlim = %lu\n", stuff->rlim);
    fprintf(out,"startcode = %lu\n", stuff->startcode);
    fprintf(out,"endcode = %lu\n", stuff->endcode);
    fprintf(out,"startstack = %lu\n", stuff->startstack);
    fprintf(out,"kstkesp = %lu\n", stuff->kstkesp);
    fprintf(out,"kstkeip = %lu\n", stuff->kstkeip);
    fprintf(out,"signal = %lu\n", stuff->signal);
    fprintf(out,"blocked = %lu\n", stuff->blocked);
    fprintf(out,"sigignore = %lu\n", stuff->sigignore);
    fprintf(out,"sigcatch = %lu\n", stuff->sigcatch);
    fprintf(out,"wchan = %lu\n", stuff->wchan);
    fprintf(out,"nswap = %lu\n", stuff->nswap);
    fprintf(out,"cnswap = %lu\n", stuff->cnswap);
    fprintf(out,"exit_signal = %d\n", stuff->exit_signal);
    fprintf(out,"processor = %d\n", stuff->processor);
    fprintf(out,"rt_priority = %lu\n", stuff->rt_priority);
    fprintf(out,"policy = %lu\n", stuff->policy);
    fprintf(out,"delayacct_blkio_ticks = %llu\n", stuff->delayacct_blkio_ticks);
}