in same file we want to write code which supports ARC and non-ARC. For that some macro required.
#ifdef ARC_ENABLED
NSLog(@" ARC enabled ");
#else
NSLog(@" ARC disabled ");
[self release];
#endif
How to achieve this macro, Does any kind of macro available? Please let me know. Advance thanks for support Note: ARC_ENABLED Just i have written for example
The following will define USING_ARC, USING_MRC & USING_GC to be 0 or 1, along with a few sanity checks:
// Utility macros (undefined below)
#define PREFIX_ONE(a) 1##a
#define EMPTY_DEFINE(a) (PREFIX_ONE(a) == 1)
// Memory management kind
#if !defined(USING_GC)
# if defined(__OBJC_GC__)
# define USING_GC 1
# else
# define USING_GC 0
# endif
#elif EMPTY_DEFINE(USING_GC)
# undef USING_GC
# define USING_GC 1
#endif
#if !defined(USING_ARC)
# if __has_feature(objc_arc)
# define USING_ARC 1
# else
# define USING_ARC 0
# endif
#elif EMPTY_DEFINE(USING_ARC)
# undef USING_ARC
# define USING_ARC 1
#endif
#if !defined(USING_MRC)
# if USING_ARC || USING_GC
# define USING_MRC 0
# else
# define USING_MRC 1
# endif
#elif EMPTY_DEFINE(USING_MRC)
# undef USING_MRC
# define USING_MRC 1
#endif
// Remove utility
#undef PREFIX_ONE
#undef EMPTY_DEFINE
// Sanity checks
#if USING_GC
# if USING_ARC || USING_MRC
# error "Cannot specify GC and RC memory management"
# endif
#elif USING_ARC
# if USING_MRC
# error "Cannot specify ARC and MRC memory management"
# endif
#elif !USING_MRC
# error "Must specify GC, ARC or MRC memory management"
#endif
#if USING_ARC
# if MAC_OS_X_VERSION_MIN_REQUIRED < MAC_OS_X_VERSION_10_6
# error "ARC requires at least 10.6"
# endif
#endif
Place that in a suitable .h included in your project .pch
You can now #if USING_x to control conditional compilation anywhere.
Also you can rule out some files from compiling under certain memory models by including, for example, at the top of the file:
#if USING_GC | USING_ARC
#error "Sorry, this file only works with MRC"
#endif