Apple Darwin Manuel d'utilisateur télécharger pdf (Page 16)

Before you begin to update your code, you should familiarize yourself with the document Mac Technology

Overview . After reading that document, the first thing you should do is compile your code with the -Wall

compiler flag and fix any warnings that occur. In particular, make sure that all function prototypes are in scope,

because out-of-scope prototypes can hide many subtle portability problems.

At a high level, to make your code 64-bit clean, you must do the following:

●

Avoid assigning 64-bit long integers to 32-bit integers.

●

Avoid assigning 64-bit pointers to 32-bit integers.

●

Fix alignment issues caused by changes in data type sizes.

●

Avoid pointer and long integer truncation during arithmetic operations.

General Programming Tips

This section contains some general tips for making your code 64-bit clean.

Update architecture-specific code. If your software contains any architecture-specific code, you must either

add extra code for each additional architecture or modify your preprocessor directives so that the same code

is included for multiple supported architectures.

Unless you are including inline assembly language code, you should generally test for the presence of

architecture-neutral macros such as __LITTLE_ENDIAN__ or __LP64__ rather than testing for a specific

processor architecture.

The macro __LP64__ can be used to test for LP64 compilation in an architecture-independent way. For example:

#ifdef __LP64__

// 64-bit code

#else

// 32-bit code

#endif

Making Code 64-Bit Clean

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Apple Darwin Manuel d'utilisateur Page 16