Internet connection Detection

 

Ideas:

 

1. First, check the current Nic status. If the NIC status is down, there is no need to perform the following test and it is determined that bool checknetstatus () is not connected to the Internet ()

2. If the NIC status is up, check whether a URL int checknet (char * URL, char * keystr) can be accessed)

 

 

 

Check the status of the current Nic. If the NIC status is down, you do not need to perform the following test to determine that the NIC is not connected to the Internet.

 

Bool checknetstatus ()

Bool checknetstatus () <br/>{< br/> bool netstatus = true; // The default status is networked <br/> pmib_iftable iftable; <br/> DWORD dwsize = 0; <br/> DWORD dwretval = 0; <br/> mib_ifrow ifrow; <br/> // allocate memory for our pointers. <br/> iftable = (mib_iftable *) malloc (sizeof (mib_iftable); <br/> // obtain the test result, obtain enough space <br/> If (getiftable (iftable, & dwsize, 0) = error_insufficient_buffer) {<br/> // release the space applied before the iftable, not processed <br/> iftable = (Mib_iftable *) malloc (dwsize); <br/>}< br/> // obtain <br/> If (dwretval = getiftable (iftable, & dwsize, 0) = no_error) <br/> {<br/> for (INT I = 0; I <(INT) iftable-> dwnumentries; I ++) <br/> {<br/> ifrow = iftable-> table [I]; <br/> char * PTR = (char *) (ifrow. bdescr); <br/> wtolower (PTR); <br/> If (strstr (PTR, "USB") | strstr (PTR, "loopback ")) <br/> continue; <br/> dwretval = getifentry (& ifrow); <br/> If (if Row. dwadminstatus = mib_if_admin_status_down) <br/> netstatus = false; <br/> else <br/> netstatus = true; <br/>}< br/> else <br/> {<br/> const char * notice11 = "getiftable failed .! "; <Br/> log (notice11, strlen (notice11); <br/>}< br/> free (iftable); <br/> return netstatus; <br/>}< br/> 

Check whether a website can be accessed

# Include <PM. h> <br/> # include <iphlpapi. h> <br/> # pragma comment (Lib, "iphlpapi. lib ") <br/> # define maxsize 4096 <br/> # pragma comment (Lib," wininet. lib ") <br/> int checknet (char * URL, char * keystr) <br/>{< br/> int flag = 0; <br/> hinternet hsession = internetopen (_ T ("urltest"), internet_open_type_preconfig, null, null, 0); <br/> If (hsession! = NULL) <br/>{< br/> wchar_t * Wurl = short2wide (URL); <br/> hinternet hhttp = internetopenurl (hsession, Wurl, null, 0, internet_flag_dont_cache, 0); <br/> If (hhttp! = NULL) <br/>{< br/> char temp [maxsize]; <br/> ulong number = 1; <br/> while (number> 0) <br/>{< br/> memset (temp, 0, maxsize); <br/> internetreadfile (hhttp, temp, maxsize-1, & number ); <br/> If (strstr (temp, keystr )! = 0) <br/>{< br/> flag = 1; <br/> continue; <br/>}< br/> internetclosehandle (hhttp); <br/> hhttp = NULL; <br/>}< br/> internetclosehandle (hsession); <br/> hsession = NULL; <br/>}< br/> return flag; <br/>}