iso8601basic nanosecond precision timestamp format + uuid

00__iso8601basic nanosecond precision timestamp format + uuid.md

iso8601basic nanosecond precision timestamp format + uuid

iso8601basic + uuid

YYYYMMDDTHHMMSSnnnnnnnnnZuuid

4     YYYY         Year (4 digits)
2     MM           Month (2 digits, 01-12)
2     DD           Day of the month (2 digits, 01-31)
1     T            Separator between date and time
2     HH           Hour (2 digits, 00-24)
2     MM           Minutes (2 digits, 00-59)
2     SS           Seconds (2 digits, 00-60)
9     nnnnnnnnn    Nanoseconds (9 digits)
1     Z            Time zone designator (Z for UTC, +/-HHMM for offset from UTC)
32    uuid         128-bit UUID (Universal Unique Identifier)

Example output:
20231220T092700921579500Z6a598740ac3e4f75b32ed23f096bcbc2

╭─    iso8601basic      ╮
YYYYMMDDTHHMMSSnnnnnnnnnZ              uuid
╭──╮╭╮╭╮│╭╮╭╮╭╮╭───────╮│╭──────────────────────────────╮
20231220T092700921579500Z6a598740ac3e4f75b32ed23f096bcbc2

01__timestamp_with_comments.c	raw
02__timestamp.c	raw

01__timestamp_with_comments.c

/*
    Filename:

    timestamp.c


    Description:

    This program generates a timestamp in ISO8601 format, appends a hyphen-free UUID to it,
    and prints the result. The timestamp includes the date, time, and nanoseconds.


    Compile Command:

    gcc -o timestamp.exe timestamp.c -lrpcrt4


    Example Output:

    20231220T092700921579500Z6a598740ac3e4f75b32ed23f096bcbc2

    ╭─    iso8601basic      ╮
    YYYYMMDDTHHMMSSnnnnnnnnnZ              uuid
    ╭──╮╭╮╭╮│╭╮╭╮╭╮╭───────╮│╭──────────────────────────────╮
    20231220T092700921579500Z6a598740ac3e4f75b32ed23f096bcbc2
*/


// Include the Standard Input/Output library
#include <stdio.h>


// Include the Time library
#include <time.h>


// Include the Windows-specific headers
#include <windows.h>


// Include the RPC library for UUID functions
#include <rpc.h>


// Entry point of the program
int main() {


    // Declare a timespec structure to hold high-precision time
    struct timespec res;


    // Check the resolution of CLOCK_REALTIME and handle errors
    if (clock_getres(CLOCK_REALTIME, &res) != 0) {


        // Print an error message and return 1 if clock resolution fetching fails
        printf("Failed to get clock resolution\n");


        // Return 1 to indicate an error occurred
        return 1;
    }


    // Declare a pointer to a struct tm for broken-down time
    struct tm *tm;


    // Declare a buffer to hold the formatted date-time string
    char buf[30];


    // Declare a string to hold the UUID including hyphens
    char uuid_str[37];


    // Declare a string to hold the UUID without hyphens
    char uuid_no_hyphens[33];


    // Fetch the current time and store it in res
    clock_gettime(CLOCK_REALTIME, &res);


    // Convert the time in seconds to GMT/UTC
    tm = gmtime(&(res.tv_sec));


    // Format the time into a string in the specified format
    strftime(buf, sizeof(buf), "%Y%m%dT%H%M%S", tm);


    // Declare a UUID variable
    UUID uuid;


    // Generate a new UUID
    UuidCreate(&uuid);


    // Declare a variable to hold the RPC string
    RPC_CSTR uuid_rpc_str;


    // Convert the UUID to a string
    UuidToStringA(&uuid, &uuid_rpc_str);


    // Copy the UUID string to uuid_str
    strncpy(uuid_str, (char*)uuid_rpc_str, 36);


    // Ensure null termination of the UUID string
    uuid_str[36] = '\0';


    // Initialize a variable for indexing through uuid_no_hyphens
    int j = 0;


    // Iterate over the UUID string
    for (int i = 0; i < 36; i++) {


        // Check if the current character is not a hyphen
        if (uuid_str[i] != '-') {


            // Copy non-hyphen characters to uuid_no_hyphens
            uuid_no_hyphens[j++] = uuid_str[i];
        }
    }


    // Null-terminate the new UUID string
    uuid_no_hyphens[j] = '\0';


    // Print the formatted date-time string with nanoseconds and the hyphen-free UUID
    printf("%s%09ldZ%s\n", buf, res.tv_nsec, uuid_no_hyphens);


    // Free the memory allocated for the UUID string
    RpcStringFreeA(&uuid_rpc_str);


    // Return 0 indicating successful execution
    return 0;
}

02__timestamp.c

#include <stdio.h>
#include <time.h>
#include <windows.h>
#include <rpc.h>

int main() {
    struct timespec res;

    if (clock_getres(CLOCK_REALTIME, &res) != 0) {
        printf("Failed to get clock resolution\n");
        return 1;
    }

    struct tm *tm;
    char buf[30];
    char uuid_str[37];
    char uuid_no_hyphens[33];

    clock_gettime(CLOCK_REALTIME, &res);
    tm = gmtime(&(res.tv_sec));
    strftime(buf, sizeof(buf), "%Y%m%dT%H%M%S", tm);

    UUID uuid;
    UuidCreate(&uuid);

    RPC_CSTR uuid_rpc_str;
    UuidToStringA(&uuid, &uuid_rpc_str);
    strncpy(uuid_str, (char*)uuid_rpc_str, 36);
    uuid_str[36] = '\0';

    int j = 0;
    for (int i = 0; i < 36; i++) {
        if (uuid_str[i] != '-') {
            uuid_no_hyphens[j++] = uuid_str[i];
        }
    }
    uuid_no_hyphens[j] = '\0';

    printf("%s%09ldZ%s\n", buf, res.tv_nsec, uuid_no_hyphens);

    RpcStringFreeA(&uuid_rpc_str);

    return 0;
}