AIX Version 4.3 Differences Guide

• Fixed width types are used in all header files. The following are the fixed width
types: char, short, int, and long long. (Of course, these types are only fixed
with respect to AIX.)
Note: Pointers exist in some of the existing header files. Since pointers are
not fixed-width types, source code using these pointers will not compile in
64-bit mode.
• Source code compatibility is maintained for 32-bit programs written to process
32-bit XCOFF files.
• Minimal changes are required to port a 32-bit program that manipulates 32-bit
XCOFF files to a 32-bit program that manipulates 64-bit XCOFF files.
• Minimal changes are required to port a 32-bit program that manipulates 32-bit
XCOFF files to a 64-bit program that manipulates 32-bit XCOFF files.
3.2.3.2 Using the XCOFF Formats
There are different options for an application to use the XCOFF formats. The
following strategies are possible:
• Using 32-bit XCOFF declarations.
To only use the 32-bit XCOFF definitions, an application must include the
appropriate header files. This will define only the structures for 32-bit XCOFF
files. The 64-bit XCOFF structures and field names will not be defined.
Structure names and field names will match those in previous versions of AIX,
providing source compatibility.
Note: Existing uses of shorthand type notation (for example, uint, ulong) have
been removed.
• Using 64-bit XCOFF declarations.
To only use the 64-bit XCOFF definitions, an application must define the
preprocessor macro __XCOFF64__ . This will define only the structures for
64-bit XCOFF files. The 32-bit XCOFF structures and field names will not be
defined. Structure names and field names will match the 32-bit XCOFF
versions.
• Using both XCOFF declarations.
To use separate 32-bit XCOFF and 64-bit XCOFF definitions, an application
must define both the preprocessor macros __XCOFF32__ and
__XCOFF64__. This will define structures for both kinds of XCOFF files.
Structure and typedef names for 64-bit XCOFF will have the suffix _64 added
to them, even if a common structure could be used.
• Using a hybrid of both XCOFF declarations.
To use a hybrid of both the 32-bit XCOFF and 64-bit XCOFF definitions, an
application must define the preprocessor macro __XCOFF_HYBRID__. This
will define single structures that can be used with both 32-bit XCOFF and
64-bit XCOFF, where possible. Where fields in structures are a different size
or at a different offset, suffixes 32 and 64 are used to differentiate between the
fields. For example, the symbol table definition (in /usr/include/syms.h) will
have the names n_offset32 and n_offset64, which should be used for 32-bit
XCOFF and 64-bit XCOFF files respectively.
64-Bit Enablement 47