获取ios手机的mac地址的函数

 由于需要向服务器发送，本应用的活跃手机量。通过获取手机的唯一标示符UUID或者MAC地址。由于IOS5以后，不支持获取uuid，因此获取MAC地址。下面的代码复用率极高，可以作为很重要的参考。

#pragma mark MAC

// Return the local MAC addy

// Courtesy of FreeBSD hackers email list

// Accidentally munged during previous update. Fixed thanks to mlamb.

- (NSString *) macaddress

{

int mib[6];

size_t len;

char *buf;

unsigned char *ptr;

struct if_msghdr *ifm;

struct sockaddr_dl *sdl;

mib[0] = CTL_NET;

mib[1] = AF_ROUTE;

mib[2] = 0;

mib[3] = AF_LINK;

mib[4] = NET_RT_IFLIST;

if ((mib[5] = if_nametoindex("en0")) == 0) {

printf("Error: if_nametoindex error/n");

return NULL;

}

if (sysctl(mib, 6, NULL, &len, NULL, 0) < 0) {

printf("Error: sysctl, take 1/n");

return NULL;

}

if ((buf = malloc(len)) == NULL) {

printf("Could not allocate memory. error!/n");

return NULL;

}

if (sysctl(mib, 6, buf, &len, NULL, 0) < 0) {

printf("Error: sysctl, take 2");

return NULL;

}

ifm = (struct if_msghdr *)buf;

sdl = (struct sockaddr_dl *)(ifm + 1);

ptr = (unsigned char *)LLADDR(sdl);

NSString *outstring = [NSString stringWithFormat:@"%02x%02x%02x%02x%02x%02x", *ptr, *(ptr+1), *(ptr+2), *(ptr+3), *(ptr+4), *(ptr+5)];

free(buf);

return [outstring uppercaseString];

}