我试图理解下面 Arduino 草图中的“if (strcmp(URL, "/") == 0)”行(请参阅大约一半的 sendMyPage 函数):
#include <WiServer.h>
#define WIRELESS_MODE_INFRA 1
#define WIRELESS_MODE_ADHOC 2
#define AREF_VOLTAGE 5
const int tmpPin = A0;
int tmpReading = 0;
// Wireless configuration parameters ----------------------------------------
unsigned char local_ip[] = {192,168,31,199}; // IP address of WiShield
unsigned char gateway_ip[] = {192,168,1,1}; // router or gateway IP address
unsigned char subnet_mask[] = {255,255,255,0}; // subnet mask for the local network
const prog_char ssid[] PROGMEM = {"MERCURY_7F3F70"}; // max 32 bytes
unsigned char security_type = 3; // 0 - open; 1 - WEP; 2 - WPA; 3 - WPA2
// WPA/WPA2 passphrase
const prog_char security_passphrase[] PROGMEM = {"11163127"}; // max 64 characters
// WEP 128-bit keys
// sample HEX keys
prog_uchar wep_keys[] PROGMEM = { 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, // Key 0
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // Key 1
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // Key 2
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 // Key 3
};
// setup the wireless mode
// infrastructure - connect to AP
// adhoc - connect to another WiFi device
unsigned char wireless_mode = WIRELESS_MODE_INFRA;
unsigned char ssid_len;
unsigned char security_passphrase_len;
// End of wireless configuration parameters ----------------------------------------
float testTmp (void){
tmpReading = analogRead (tmpPin);
float voltage = tmpReading * AREF_VOLTAGE;
voltage /= 1023;
float tmpC = (voltage - 0.5) * 100;
return tmpC;
}
// This is our page serving function that generates web pages
**boolean sendMyPage(char* URL)** {
// Check if the requested URL matches "/"
**if (strcmp(URL, "/") == 0) {**
// Use WiServer's print and println functions to write out the page content
float tmpC = testTmp ();
WiServer.print("<html>");
// WiServer.print("Hello World!");
WiServer.print(tmpC);
WiServer.print("</html>");
// URL was recognized
return true;
}
// URL not found
return false;
}
void setup() {
// Initialize WiServer and have it use the sendMyPage function to serve pages
WiServer.init(sendMyPage);
// Enable Serial output and ask WiServer to generate log messages (optional)
Serial.begin(57600);
WiServer.enableVerboseMode(true);
}
void loop(){
// Run WiServer
WiServer.server_task();
delay(10);
}
该函数似乎接受 URL 作为参数，如果 URL 有效，则使用 WiSever.print 将数据发送到页面。但是 'if (strcmp(URL, "/") == 0)' 如何判断 URL 是否正确呢？
我以前见过这种检查，但不明白它是如何工作的。
谢谢!
最佳答案
行:
if (strcmp(URL, "/") == 0) {
正在测试字符串 URL 是否与字符串文字“/”完全匹配。如果是，则返回0。
注意，如果您想测试字符串 URL 是否包含“/”，则使用:
if (strstr(URL, "/") != NULL) {
关于但是'if (strcmp(URL, "/") == 0)'如何判断URL是否正确呢？
它不是。需要更多的字符来确定 URL 是否正确，所写的注释似乎并没有真正表达该代码块的实际用途。
关于c - "if (strcmp(URL, "/") == 0)"在Arduino网络草图中的使用，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/23200430/