项目需要用到判断设备型号，于是研究了一下，把总结的copy到下面（已更新到se）。直接上代码：

// pragma mark 判断设备的型号
+ (NSString *)platformString {
    
    // Gets a string with the device model
    size_t size;
    int nR = sysctlbyname("hw.machine", NULL, &size, NULL, 0);
    char *machine = (char *)malloc(size);
    nR = sysctlbyname("hw.machine", machine, &size, NULL, 0);
    NSString *platform = [NSString stringWithCString:machine encoding:NSUTF8StringEncoding];
    free(machine);
    
    // iPhone======
    
    if ([platform isEqualToString:@"iPhone1,1"]) return @"iPhone 1";
    
    if ([platform isEqualToString:@"iPhone1,2"]) return @"iPhone 3";
    
    if ([platform isEqualToString:@"iPhone2,1"]) return @"iPhone 3GS";
    
    if ([platform isEqualToString:@"iPhone3,1"]) return @"iPhone 4";
    
    if ([platform isEqualToString:@"iPhone3,2"]) return @"iPhone 4";
    
    if ([platform isEqualToString:@"iPhone3,3"]) return @"iPhone 4";
    
    if ([platform isEqualToString:@"iPhone4,1"]) return @"iPhone 4s";
    
    if ([platform isEqualToString:@"iPhone5,1"]) return @"iPhone 5";
    
    if ([platform isEqualToString:@"iPhone5,2"]) return @"iPhone 5";
    
    if ([platform isEqualToString:@"iPhone5,3"]) return @"iPhone 5C";
    
    if ([platform isEqualToString:@"iPhone5,4"]) return @"iPhone 5C";
    
    if ([platform isEqualToString:@"iPhone6,1"]) return @"iPhone 5S";
    
    if ([platform isEqualToString:@"iPhone6,2"]) return @"iPhone 5S";
    
    if ([platform isEqualToString:@"iPhone7,1"]) return @"iPhone 6";
    
    if ([platform isEqualToString:@"iPhone7,2"]) return @"iPhone 6 Plus";
    
    if ([platform isEqualToString:@"iPhone8,1"]) return @"iPhone 6s";
    
    if ([platform isEqualToString:@"iPhone8,2"]) return @"iPhone 6s Plus";
    
    if ([platform isEqualToString:@"iPhone8,4"]) return @"iPhone SE";
    
    // iPot Touch======
    
    if ([platform isEqualToString:@"iPod1,1"]) return @"iPod Touch";
    
    if ([platform isEqualToString:@"iPod2,1"]) return @"iPod Touch 2";
    
    if ([platform isEqualToString:@"iPod3,1"]) return @"iPod Touch 3";
    
    if ([platform isEqualToString:@"iPod4,1"]) return @"iPod Touch 4";
    
    if ([platform isEqualToString:@"iPod5,1"]) return @"iPod Touch 5";
    
    // iPad======
    
    if ([platform isEqualToString:@"iPad1,1"]) return @"iPad";
    
    if ([platform isEqualToString:@"iPad2,1"]) return @"iPad 2";
    
    if ([platform isEqualToString:@"iPad2,2"]) return @"iPad 2";
    
    if ([platform isEqualToString:@"iPad2,3"]) return @"iPad 2";
    
    if ([platform isEqualToString:@"iPad2,4"]) return @"iPad 2";
    
    if ([platform isEqualToString:@"iPad2,5"]) return @"iPad Mini 1";
    
    if ([platform isEqualToString:@"iPad2,6"]) return @"iPad Mini 1";
    
    if ([platform isEqualToString:@"iPad2,7"]) return @"iPad Mini 1";
    
    if ([platform isEqualToString:@"iPad3,1"]) return @"iPad 3";
    
    if ([platform isEqualToString:@"iPad3,2"]) return @"iPad 3";
    
    if ([platform isEqualToString:@"iPad3,3"]) return @"iPad 3";
    
    if ([platform isEqualToString:@"iPad3,4"]) return @"iPad 4";
    
    if ([platform isEqualToString:@"iPad3,5"]) return @"iPad 4";
    
    if ([platform isEqualToString:@"iPad3,6"]) return @"iPad 4";
    
    if ([platform isEqualToString:@"iPad4,1"]) return @"iPad air";
    
    if ([platform isEqualToString:@"iPad4,2"]) return @"iPad air";
    
    if ([platform isEqualToString:@"iPad4,3"]) return @"iPad air";
    
    if ([platform isEqualToString:@"iPad4,4"]) return @"iPad mini 2";
    
    if ([platform isEqualToString:@"iPad4,5"]) return @"iPad mini 2";
    
    if ([platform isEqualToString:@"iPad4,6"]) return @"iPad mini 2";
    
    if ([platform isEqualToString:@"iPad4,7"]) return @"iPad mini 3";
    
    if ([platform isEqualToString:@"iPad4,8"]) return @"iPad mini 3";
    
    if ([platform isEqualToString:@"iPad4,9"]) return @"iPad mini 3";
    
    if ([platform isEqualToString:@"iPad5,3"]) return @"iPad air 2";
    
    if ([platform isEqualToString:@"iPad5,4"]) return @"iPad air 2";
    
    // 模拟器======
    
    if ([platform isEqualToString:@"iPhone Simulator"] || [platform isEqualToString:@"x86_64"]) return @"iPhone Simulator";
    
    return @"型号未知";
}

因为苹果用的硬件编码识别，具体可以参考：https://www.theiphonewiki.com/wiki/Models