ios - Testing connectivity / availability of IP Address in Objective C -

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basically able check whether particular host on local network "up".

the following line of code hangs when host unreachable, i'd perform check first before running it.

    [_outputstream write:[data bytes] maxlength:[data length]];

a similar query think answered in following link, think need use cfhostcreatewithaddress rather cfhostcreatewithname

alternatives nshost in iphone app

here attempt @ i'm trying do...

boolean result; struct sockaddr_in address;  address.sin_family = af_inet; address.sin_port = htons(80); inet_pton(af_inet, "192.168.1.31", &address.sin_addr);  cfdataref sockdata = cfdatacreate(null, &address, sizeof(address)); cfhostref host = cfhostcreatewithaddress(null, sockdata); result = cfhoststartinforesolution(host, kcfhostaddresses, null);  if (result == true) {     nslog(@"resolved"); } else {     nslog(@"not resolved"); }

even when host not resolved.

below attempt use reachability class. code telling me below address reachable despite there being no host @ specified address.

struct sockaddr_in address;  address.sin_family = af_inet; address.sin_port = htons(80); inet_pton(af_inet, "192.168.1.31", &address.sin_addr);  reachability *reachability = [reachability reachabilitywithaddress:&address]; networkstatus reachabilitytohost = [reachability currentreachabilitystatus]; if(reachabilitytohost != notreachable) {     nslog(@"reachable"); } else {     nslog(@"not reachable"); }

add reachability class project.

 #import "reachability.h"

also add systemconfiguration framework.

reachability *reachability = [reachability reachabilitywithhostname:@"www.example.com"]; networkstatus reachabilitytohost = [reachability currentreachabilitystatus]; if(reachabilitytohost != notreachable) {     //reachable } else {     // not reachable }

check sample code here: https://developer.apple.com/library/ios/samplecode/reachability/introduction/intro.html

for more info: https://developer.apple.com/library/ios/samplecode/reachability/listings/reachability_reachability_h.html


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