Just in case one of those cats care if they can use C on the iPhone, here is how you obtain MAC address of the device.
Code:
#pragma mark -
#pragma mark Private Methods
// Return the local MAC addy
// Courtesy of FreeBSD hackers email list
// Accidentally munged during previous update. Fixed thanks to erica sadun & 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;
}
Source: stackoverflow.com.
The UI part of the code needs to be in ObjC as the UI frameworks are all in ObjC. The invisible parts of the application can use crypto, compression, image manipulation, networking, file/database manipulation libraries like ZLIB for example as they are, pure C, no problem. You can call C functions from ObjC methods and vice versa since ObjC is just a superset of C.