This is sockets/socknames.c (Listing 61-3, page 1265), an example from the book, The Linux Programming Interface.

The source code file is copyright 2023, Michael Kerrisk, and is licensed under the GNU General Public License, version 3.

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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.


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  Cover of The Linux Programming Interface

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

#include "inet_sockets.h"               /* Declares our socket functions */
#include "tlpi_hdr.h"
main(int argc, char *argv[])
    int listenFd, acceptFd, connFd;
    socklen_t len;                      /* Size of socket address buffer */
    void *addr;                         /* Buffer for socket address */
    char addrStr[IS_ADDR_STR_LEN];

    if (argc != 2 || strcmp(argv[1], "--help") == 0)
        usageErr("%s service\n", argv[0]);

    listenFd = inetListen(argv[1], 5, &len);
    if (listenFd == -1)

    connFd = inetConnect(NULL, argv[1], SOCK_STREAM);
    if (connFd == -1)

    acceptFd = accept(listenFd, NULL, NULL);
    if (acceptFd == -1)

    addr = malloc(len);
    if (addr == NULL)

    if (getsockname(connFd, addr, &len) == -1)
    printf("getsockname(connFd):   %s\n",
            inetAddressStr(addr, len, addrStr, IS_ADDR_STR_LEN));
    if (getsockname(acceptFd, addr, &len) == -1)
    printf("getsockname(acceptFd): %s\n",
            inetAddressStr(addr, len, addrStr, IS_ADDR_STR_LEN));

    if (getpeername(connFd, addr, &len) == -1)
    printf("getpeername(connFd):   %s\n",
            inetAddressStr(addr, len, addrStr, IS_ADDR_STR_LEN));
    if (getpeername(acceptFd, addr, &len) == -1)
    printf("getpeername(acceptFd): %s\n",
            inetAddressStr(addr, len, addrStr, IS_ADDR_STR_LEN));

    sleep(30);                          /* Give us time to run netstat(8) */


Download sockets/socknames.c

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