pselect.lc

unix网络编程第一卷socket编程书上的全部源代码

/*##  1 ##src/lib/pselect.c##
 * This is *not* a complete implementation of the Posix.1g pselect()##  2 ##src/lib/pselect.c##
 * function.  For atomicity this must be implemented within the kernel,##  3 ##src/lib/pselect.c##
 * with the sigprocmask/select/sigprocmask performed as a single atomic##  4 ##src/lib/pselect.c##
 * operation.##  5 ##src/lib/pselect.c##
 * This is just a quick hack to allow simple programs using it to compile.##  6 ##src/lib/pselect.c##
 * Using such programs with this hack will probably lead to race conditions.##  7 ##src/lib/pselect.c##
 */##  8 ##src/lib/pselect.c##
/* include pselect */
#include    "unp.h"##  9 ##src/lib/pselect.c##

int## 10 ##src/lib/pselect.c##
pselect(int nfds, fd_set *rset, fd_set *wset, fd_set *xset,## 11 ##src/lib/pselect.c##
        const struct timespec *ts, const sigset_t *sigmask)## 12 ##src/lib/pselect.c##
{## 13 ##src/lib/pselect.c##
    int     n;## 14 ##src/lib/pselect.c##
    struct timeval tv;## 15 ##src/lib/pselect.c##
    sigset_t savemask;## 16 ##src/lib/pselect.c##

    if (ts != NULL) {## 17 ##src/lib/pselect.c##
        tv.tv_sec = ts->tv_sec;## 18 ##src/lib/pselect.c##
        tv.tv_usec = ts->tv_nsec / 1000;    /* nanosec -> microsec */## 19 ##src/lib/pselect.c##
    }## 20 ##src/lib/pselect.c##

    sigprocmask(SIG_SETMASK, sigmask, &savemask);   /* caller's mask */## 21 ##src/lib/pselect.c##
    n = select(nfds, rset, wset, xset, (ts == NULL) ? NULL : &tv);## 22 ##src/lib/pselect.c##
    sigprocmask(SIG_SETMASK, &savemask, NULL);  /* restore mask */## 23 ##src/lib/pselect.c##

    return (n);## 24 ##src/lib/pselect.c##
}## 25 ##src/lib/pselect.c##
/* end pselect */