what library to use when using WiFiClient in C code example

Example: arduino wifi client

//This is assuming that you are connected to a network - router or other access point
#include <WiFi.h>

// Initialize the client library
WiFiClient client;

void setup() {
  	WiFi.begin(ssid, pass);	//Connect to access point
  	delay(4000);			//Allow time for connection to become established
  
	IPAddress server(192,168,2,1);  //The IPAddress of the server you're trying to connect to
	client.connect(server, 80)		//Connect to the server through the servers IP and port number
}