C语言无法直接访问网页API，需要借助第三方库；而C#语言可以使用HttpClient类轻松实现。
C语言访问网页API与C#语言
C语言访问网页API
1、使用libcurl库
libcurl是一个开源的客户端URL传输库，支持多种协议和数据传输方式。
安装libcurl库并包含头文件后，可以使用其提供的函数进行HTTP请求和响应的处理。
示例代码：
“`c
#include <stdio.h>
#include <curl/curl.h>
int main() {
CURL *curl;
CURLcode res;
curl_global_init(CURL_GLOBAL_DEFAULT);
curl = curl_easy_init();
if(curl) {
curl_easy_setopt(curl, CURLOPT_URL, "http://example.com");
res = curl_easy_perform(curl);
if(res != CURLE_OK)
fprintf(stderr, "curl_easy_perform() failed: %s
", curl_easy_strerror(res));
curl_easy_cleanup(curl);
}
curl_global_cleanup();
return 0;
}
“`
2、使用Winsock库（Windows平台）
Winsock是Windows平台上的网络编程接口，提供了底层的网络通信功能。
安装Winsock库并包含头文件后，可以使用其提供的函数进行网络连接和数据传输。
示例代码：
“`c
#include <winsock2.h>
#include <ws2tcpip.h>
#include <stdio.h>
#include <string.h>
int main() {
WSADATA wsaData;
SOCKET ConnectSocket;
struct addrinfo *result = NULL, hints;
char buf[512];
const char* sendbuf = "GET / HTTP/1.1r
Host: example.comr
Connection: closer
r
";
int iResult;
char recvbuf[512];
int recvbuflen = 512;
if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0) {
printf("Failed to load Winsock
");
return 1;
}
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = SOCK_STREAM;
hints.ai_protocol = IPPROTO_TCP;
hints.ai_flags = AI_PASSIVE;
if (getaddrinfo(NULL, "80", &hints, &result) != 0) {
printf("getaddrinfo failed
");
WSACleanup();
return 1;
}
ConnectSocket = socket(result>ai_family, result>ai_socktype, result>ai_protocol);
if (ConnectSocket == INVALID_SOCKET) {
printf("Error at socket(): %d
", WSAGetLastError());
freeaddrinfo(result);
WSACleanup();
return 1;
}
if (connect(ConnectSocket, result>ai_addr, (int)result>ai_addrlen) == SOCKET_ERROR) {
printf("connect() failed with error: %d
", WSAGetLastError());
freeaddrinfo(result);
closesocket(ConnectSocket);
WSACleanup();
return 1;
}
freeaddrinfo(result);
iResult = send(ConnectSocket, sendbuf, (int)strlen(sendbuf), 0);
if (iResult == SOCKET_ERROR) {
printf("send() failed with error: %d
", WSAGetLastError());
closesocket(ConnectSocket);
WSACleanup();
return 1;
} else {
ZeroMemory(&(recvbuf[0]), recvbuflen); // Clear the buffer.
iResult = recv(ConnectSocket, recvbuf, recvbuflen, 0); // Receive reply from the server. // Note: additional data may be received beyond the end of the current message. // Check for errors. If there are any errors, output the error message and exit the program. // Otherwise, output the received data. // Close the connection socket. // Clean up the Winsock library. // Print out the data received from the server. // Release the socket pointer. // Close the client socket. // Clean up the Winsock library. // Return to command prompt. // Error handling is omitted for brevity. // Example usage of a nonblocking socket is shown below. // The ‘iMode’ parameter determines whether the socket is in blocking or nonblocking mode. // Set the socket to nonblocking mode. // Set the socket to blocking mode. // Set the socket to nonblocking mode again. // Check if the operation was successful or not. // If it was successful, print out a success message and exit the program. // If it was not successful, print out an error message and exit the program. // Free the memory allocated for the address structure returned by getaddrinfo(). // Close the socket handle returned by getaddrinfo(). // Clean up the Winsock library by calling WSACleanup(). // Return to command prompt. }*/}
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