This is time/show_time.c (Listing 10-4, page 199), an example from the book, The Linux Programming Interface.

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

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

/* show_time.c

   A short program that allows us to see the effects of locale and timezone
   on some of the functions that deal with time.

   Try running this program with command lines such as the following:

        TZ=":Pacific/Auckland" ./show_time
        TZ=":US/Central" ./show_time
        TZ=":CET" ./show_time
#include <time.h>
#include <locale.h>
#include "tlpi_hdr.h"

#define BUF_SIZE 200
main(int argc, char *argv[])
    time_t t;
    struct tm *loc;
    char buf[BUF_SIZE];

    if (setlocale(LC_ALL, "") == NULL)
        errExit("setlocale");   /* Use locale settings in conversions */

    t = time(NULL);

    printf("ctime() of time() value is:  %s", ctime(&t));

    loc = localtime(&t);
    if (loc == NULL)

    printf("asctime() of local time is:  %s", asctime(loc));

    if (strftime(buf, BUF_SIZE, "%A, %d %B %Y, %H:%M:%S %Z", loc) == 0)
        fatal("strftime returned 0");
    printf("strftime() of local time is: %s\n", buf);



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