获取系统版本号、系统代号等相关信息。
NSProcessInfo *info = [NSProcessInfo processInfo];
NSString *build = info.operatingSystemVersionString;
NSLog(@"build：%@", build); //build：Version 12.1.4 (Build 16D57)
NSOperatingSystemVersion version = info.operatingSystemVersion;
NSInteger majorVersion = version.majorVersion;
NSInteger minorVersion = version.minorVersion;
NSInteger patchVersion = version.patchVersion;
NSLog(@"major: %ld \nminor: %ld, \npatch: %ld",majorVersion, minorVersion, patchVersion);
/*
major: 12
minor: 1,
patch: 4
*/
NSString *systemVersion = [UIDevice currentDevice].systemVersion;
NSLog(@"systemVersion: %@", systemVersion); //systemVersion: 12.1.4
