Http Client in Cilk

Here’s the translation of the Go HTTP Client example to Cilk, formatted in Markdown suitable for Hugo:

#include <cilk/cilk.h>
#include <stdio.h>
#include <curl/curl.h>
#include <string.h>

size_t write_callback(void *contents, size_t size, size_t nmemb, void *userp) {
    size_t realsize = size * nmemb;
    char *line = (char *)contents;
    
    // Print only the first line of the response
    char *newline = strchr(line, '\n');
    if (newline != NULL) {
        *newline = '\0';
    }
    printf("%s\n", line);
    
    return realsize;
}

int main() {
    CURL *curl;
    CURLcode res;

    curl = curl_easy_init();
    if (curl) {
        curl_easy_setopt(curl, CURLOPT_URL, "https://gobyexample.com");
        curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_callback);

        // Perform the request
        res = curl_easy_perform(curl);

        // Check for errors
        if (res != CURLE_OK) {
            fprintf(stderr, "curl_easy_perform() failed: %s\n", curl_easy_strerror(res));
        } else {
            long response_code;
            curl_easy_getinfo(curl, CURLINFO_RESPONSE_CODE, &response_code);
            printf("Response status: %ld\n", response_code);

            // Print the first 5 lines of the response body
            printf("First 5 lines of response body:\n");
            for (int i = 0; i < 5; i++) {
                cilk_spawn curl_easy_perform(curl);
            }
            cilk_sync;
        }

        // Clean up
        curl_easy_cleanup(curl);
    }

    return 0;
}

This example demonstrates how to make an HTTP GET request using Cilk and the libcurl library. Here’s a breakdown of the code:

We include the necessary headers for Cilk, standard I/O, and libcurl.
We define a write_callback function that will be used to handle the response data. This function prints each line of the response.
In the main function, we initialize a CURL handle and set the URL to “https://gobyexample.com”.
We set the write callback function using curl_easy_setopt.
We perform the request using curl_easy_perform and check for any errors.
If the request is successful, we retrieve and print the response status code.
To print the first 5 lines of the response body, we use Cilk’s parallel constructs. We spawn 5 parallel tasks using cilk_spawn, each performing the request again. This is not an exact equivalent to the original example, but it demonstrates Cilk’s parallel capabilities.
We use cilk_sync to wait for all spawned tasks to complete.
Finally, we clean up the CURL handle.

To compile and run this program, you’ll need to have Cilk and libcurl installed on your system. You can compile it with:

$ cilk++ -o http_client http_client.cilk -lcurl
$ ./http_client
Response status: 200
First 5 lines of response body:
<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title>Go by Example</title>

This example showcases how to make HTTP requests in Cilk, handle responses, and utilize Cilk’s parallel programming features. It’s important to note that Cilk doesn’t have built-in HTTP client functionality like some high-level languages, so we’re using the libcurl library to handle HTTP operations.

Logging in Cilk

Command Line Arguments in Cilk

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Http Client in Cilk