Use curl in Windows to implement HTTP requests

1: Download the official library

Address: http://curl.haxx.se/download.html search Win32-msvc, there are two versions of the library below, one is with SSL, one is without SSL. I downloaded both of them:

Http://curl.haxx.se/download/libcurl-7.18.0-win32-msvc.zip without SSL

Http://curl.haxx.se/download/libcurl-7.19.3-win32-ssl-msvc.zip with SSL

2: Extract

Compress the two downloaded zip packages, and save them to the E: \ source directory. The two directories are:

E: \ source \ libcurl-7.18.0-win32-msvc

E: \ source \ libcurl-7.19.3-win32-ssl-msvc

Directory and the project files including source code, Vc, and compiled DLL and Lib files. You can directly use the DLL without compiling.

3: Visual Studio Environment Settings

Without SSL: tool-> Option-> Project-> VC ++ directory-

By default, the platform is Win32. Select the directory containing the following files and add a new line:

Path to the extracted directory e: \ source \ libcurl-7.18.0-win32-msvc \ directory of the include directory, the full path is:

E: \ source \ libcurl-7.18.0-win32-msvc \ include

Then select the library file and add a new line:

The path is set to the directory where libcurl is stored. Here I set it to E: \ source \ libcurl-7.18.0-win32-msvc.

If you use an SSL package, replace it with the path E: \ source \ libcurl-7.19.3-win32-ssl-msvc.

4. Create a Win32 project. Set it by default.

Add libcurl. lib to the project's additional dependencies under the installation directory of curl.

5: source code

#include <stdio.h> #include <string.h> #include <curl/curl.h>  #define MAX_BUF      65536  char wr_buf[MAX_BUF+1]; int  wr_index;  /* * Write data callback function (called within the context of * curl_easy_perform. */ size_t write_data( void *buffer, size_t size, size_t nmemb, void *userp ) {     int segsize = size * nmemb;      /* Check to see if this data exceeds the size of our buffer. If so,     * set the user-defined context value and return 0 to indicate a     * problem to curl.     */     if ( wr_index + segsize > MAX_BUF ) {         *(int *)userp = 1;         return 0;     }      /* Copy the data from the curl buffer into our buffer */     memcpy( (void *)&wr_buf[wr_index], buffer, (size_t)segsize );      /* Update the write index */     wr_index += segsize;      /* Null terminate the buffer */     wr_buf[wr_index] = 0;      /* Return the number of bytes received, indicating to curl that all is okay */     return segsize; }   /* * Simple curl application to read the index.html file from a Web site. */ int main( void ) {     CURL *curl;     CURLcode ret;     int  wr_error;      wr_error = 0;     wr_index = 0;      /* First step, init curl */     curl = curl_easy_init();     if (!curl) {         printf("couldn't init curl ");         return 0;     }      /* Tell curl the URL of the file we're going to retrieve */     curl_easy_setopt( curl, CURLOPT_URL, "www.baidu.com" );      /* Tell curl that we'll receive data to the function write_data, and     * also provide it with a context pointer for our error return.     */     curl_easy_setopt( curl, CURLOPT_WRITEDATA, (void *)&wr_error );     curl_easy_setopt( curl, CURLOPT_WRITEFUNCTION, write_data );      /* Allow curl to perform the action */     ret = curl_easy_perform( curl );      printf( "ret = %d (write_error = %d) ", ret, wr_error );      /* Emit the page if curl indicates that no errors occurred */     if ( ret == 0 ) printf( "%s ", wr_buf );      curl_easy_cleanup( curl );      return 0; } 

6: Others

• If you need support from other libraries (such as zlib) at http://curl.haxx.se/download.html, you can also find the compiled DLL.
• There is an article using libcurl in Visual Studio on the Internet describing the steps for downloading, compiling, and setting the Environment project.
• Http://curl.haxx.se/libcurl/c/example.html has detailed sample code