call.c

unix环境高级编程的源代码

#include    "call.h"
#include    <sys/uio.h>        /* struct iovec */

/* Place the call by sending the "args" to the calling server,
 * and reading a file descriptor back. */

int
call(const char *args)
{
    int                csfd, len;
    struct iovec    iov[2];

                    /* create connection to conn server */
    if ( (csfd = cli_conn(CS_CALL)) < 0)
        err_sys("cli_conn error");

    iov[0].iov_base = CL_CALL " ";
    iov[0].iov_len  = strlen(CL_CALL) + 1;
    iov[1].iov_base = (char *) args;
    iov[1].iov_len  = strlen(args) + 1;
                            /* null at end of args always sent */
    len = iov[0].iov_len + iov[1].iov_len;
    if (writev(csfd, &iov[0], 2) != len)
        err_sys("writev error");

                    /* read back descriptor */
                    /* returned errors handled by write() */
    return( recv_fd(csfd, write) );
}