/* UnixTime is unspecified unix time stamp type.
     * Define it before compilation, for example:
     * typedef time_t UnixTime;
     *  or
     * typedef long int UnixTime;
     */
    UnixTime ut;  /* Unix timestamp to be converted */
 
    time_t thist; /* This system timestamp value */
    struct tm* ptm;
    char mysyst[20] = "\?"; /* for "sys time" */
    const char* fmt = "%d/%m/%Y %H %M %S"; /* sys?time */
    /* C Standard does not specify what's time_t epoch */
    time_t uepoch; /* Unix epoch in this system time_t */
    struct tm tmepoch;
    /* Prepare unix time epoch on this system */
    memset(&tmepoch,0,sizeof tmepoch);
    tmepoch.tm_year = 1970 - 1900;
    tmepoch.tm_mon = 1 - 1;
    tmepoch.tm_mday = 1;
    tmepoch.tm_hour = 0;
    tmepoch.tm_min = 0;
    tmepoch.tm_sec = 0;
    uepoch = mktime(&tmepoch); /* this system unix epoch */
    /* Recalculate unix time to this system time_t */
    thist = (time_t)ut - uepoch;
    ptm = gmtime(&thist); 
    if (ptm && strftime(mysyst,sizeof mysyst,fmt,ptm))
        printf("%s\n",mysyst);