LFCOMPILE64(5) Standards, Environments, and Macros LFCOMPILE64(5)


NAME


lfcompile64 - transitional compilation environment

DESCRIPTION


All 64-bit applications can manipulate large files by default. The
transitional interfaces described on this page can be used by 32-bit and
64-bit applications to manipulate large files.


In the transitional compilation environment, explicit 64-bit functions,
structures, and types are added to the API. Compiling in this
environment allows both 32-bit and 64-bit applications to access files
whose size is greater than or equal to 2 Gbyte ( 2^31 bytes).


The transitional compilation environment exports all the explicit 64-bit
functions (xxx64()) and types in addition to all the regular functions
(xxx()) and types. Both xxx() and xxx64() functions are available to the
program source. A 32-bit application must use the xxx64() functions in
order to access large files. See the lf64(5) manual page for a complete
listing of the 64-bit transitional interfaces.


The transitional compilation environment differs from the large file
compilation environment, wherein the underlying interfaces are bound to
64-bit functions, structures, and types. An application compiled in the
large file compilation environment is able to use the xxx() source
interfaces to access both large and small files, rather than having to
explicitly utilize the transitional xxx64() interface calls to access
large files. See the lfcompile(5) manual page for more information
regarding the large file compilation environment.


Applications may combine objects produced in the large file compilation
environment with objects produced in the transitional compilation
environment, but must be careful with respect to interoperability between
those objects. Applications should not declare global variables of types
whose sizes change between compilation environments.


For applications that do not wish to conform to the POSIX or X/Open
specifications, the 64-bit transitional interfaces are available by
default. No compile-time flags need to be set.

Access to Additional Large File Interfaces


Applications that wish to access the transitional interfaces as well as
the POSIX or X/Open specification-conforming interfaces should use the
following compilation methods and set whichever feature test macros are
appropriate to obtain the desired environment (see standards(5)).

o Set the compile-time flag _LARGEFILE64_SOURCE to 1 before
including any headers.

o Use the getconf(1) command with one or more of the following
arguments:


+----------------+---------------------------------------------------------------------------------------+
| argument | purpose |
+----------------+---------------------------------------------------------------------------------------+
|LFS64_CFLAGS | obtain compilation flags necessary to enable the transitional compilation environment |
|LFS64_LDFLAGS | obtain link editor options |
|LFS64_LIBS | obtain link library names |
|LFS64_LINTFLAGS | obtain lint options |
+----------------+---------------------------------------------------------------------------------------+

EXAMPLES


In the following examples, the transitional compilation environment is
accessed by invoking the getconf utility with one of the arguments listed
in the table above. The additional large file interfaces are accessed
either by specifying -D_LARGEFILE64_SOURCE or by invoking the getconf
utility with the arguments listed above.


The example that uses the form of command substitution specifying the
command within parentheses preceded by a dollar sign can be executed only
in a POSIX-conforming shell such as the Korn Shell (see ksh(1)). In a
shell that is not POSIX-conforming, such as the Bourne Shell (see sh(1))
and the C Shell (see csh(1)), the command must be enclosed within grave
accent marks.

Example 1: An example of compiling a program using transitional interfaces


such as lseek64() and fopen64():

$ c89 -D_LARGEFILE64_SOURCE \
$(getconf LFS64_CFLAGS) a.c \
$(getconf LFS64_LDFLAGS) \
$(getconf LFS64_LIBS)


Example 2: An example of running lint on a program using transitional


interfaces:

% lint -D_LARGEFILE64_SOURCE \
`getconf LFS64_LINTFLAGS` ... \
`getconf LFS64_LIBS`


SEE ALSO


getconf(1), lseek(2), fopen(3C), lf64(5), standards(5)


January 26, 1998 LFCOMPILE64(5)