How do C++ functions handle DNS queries in network programming?
C The standard library provides functions to handle DNS queries in network programming: gethostbyname(): Find host information based on the host name. gethostbyaddr(): Find host information based on IP address. dns_lookup(): Asynchronously resolve DNS.

C function DNS query processing in network programming
In network programming, the Domain Name System (DNS) is crucial for resolving domain names into IP addresses important. The C standard library provides powerful functions to simplify this process.
Function introduction
The functions used for DNS query in the C standard library include:
-
gethostbyname(): Find the host based on the host name information. -
gethostbyaddr(): Find host information based on IP address. -
dns_lookup(): Asynchronously resolve DNS based on hostname or IP address.
Practical case
Suppose we want to obtain the IP address of www.google.com and display the results. Here is a code example using gethostbyname():
#include <netdb.h>
#include <iostream>
int main() {
// 获取主机名
std::string hostname = "www.google.com";
// 获取主机信息
struct hostent *host = gethostbyname(hostname.c_str());
// 检查是否有错误
if (!host) {
std::cerr << "gethostbyname() failed" << std::endl;
return EXIT_FAILURE;
}
// 输出 IP 地址
std::cout << "IP 地址:" << host->h_addr_list[0] << std::endl;
return EXIT_SUCCESS;
}The above is the detailed content of How do C++ functions handle DNS queries in network programming?. For more information, please follow other related articles on the PHP Chinese website!
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