This is sockets/us_xfr_v2_cl.c, an example to accompany the book, The Linux Programming Interface.

This file is not printed in the book; it is the solution to Exercise 59-3:e (page 1237).

The source code file is copyright 2022, Michael Kerrisk, and is licensed under the GNU General Public License, version 3.

In the listing below, the names of Linux system calls and C library functions are hyperlinked to manual pages from the Linux man-pages project, and the names of functions implemented in the book are hyperlinked to the implementations of those functions.


Download sockets/us_xfr_v2_cl.c

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Function list (Bold in this list means a function is not static)

/* us_xfr_v2_cl.c

   An example UNIX domain stream socket client. This client transmits contents
   of stdin to a server socket. This program is similar to us_xfr_cl.c, except
   that it uses the functions in unix_sockets.c to simplify working with UNIX
   domain sockets.

   See also us_xfr_v2_sv.c.
#include "us_xfr_v2.h"
main(int argc, char *argv[])
    int sfd = unixConnect(SV_SOCK_PATH, SOCK_STREAM);
    if (sfd == -1)

    /* Copy stdin to socket */

    ssize_t numRead;
    char buf[BUF_SIZE];

    while ((numRead = read(STDIN_FILENO, buf, BUF_SIZE)) > 0)
        if (write(sfd, buf, numRead) != numRead)
            fatal("partial/failed write");

    if (numRead == -1)

    exit(EXIT_SUCCESS);     /* Closes our socket; server sees EOF */


Download sockets/us_xfr_v2_cl.c

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