curl

Explanation of Using the curl Command in C

To use the curl command in C, you need to include the appropriate header file and use the necessary functions and structures provided by the libcurl library. Here is an explanation of the steps involved:

  1. Include the curl header file: To use the curl command in C, you need to include the curl/curl.h header file in your code. This file contains the necessary function prototypes, constants, and structures required for making HTTP requests using libcurl.

c #include <curl/curl.h>

  1. Initialize the libcurl library: Before making any HTTP requests, you need to initialize the libcurl library using the curl_global_init() function. This function sets up the necessary resources and configurations required by libcurl.

c curl_global_init(CURL_GLOBAL_DEFAULT);

  1. Create a CURL handle: A CURL handle is a pointer to a structure that holds the state and configuration of an HTTP request. You can create a CURL handle using the curl_easy_init() function.

c CURL* curl = curl_easy_init();

  1. Set the request URL: Use the curl_easy_setopt() function to set the URL of the request. Pass the CURL handle, the option CURLOPT_URL, and the URL string as arguments.

c curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");

  1. Perform the request: To perform the HTTP request, use the curl_easy_perform() function. Pass the CURL handle as an argument. This function will block until the request is completed.

c CURLcode res = curl_easy_perform(curl);

  1. Handle the response: After the request is completed, you can handle the response using the res variable. If the request was successful, res will be CURLE_OK. You can then access the response data using the appropriate libcurl functions.

c if (res == CURLE_OK) { // Handle the response }

  1. Cleanup: After you are done with the CURL handle and libcurl, you should clean up the resources to avoid memory leaks. Use the curl_easy_cleanup() function to free the CURL handle and the curl_global_cleanup() function to clean up the libcurl library.

c curl_easy_cleanup(curl); curl_global_cleanup();

These are the basic steps involved in using the curl command in C to make HTTP requests using the libcurl library. You can find more information and examples in the libcurl documentation [1].