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Diffstat (limited to 'manual/creature.texi')
-rw-r--r-- | manual/creature.texi | 65 |
1 files changed, 63 insertions, 2 deletions
diff --git a/manual/creature.texi b/manual/creature.texi index 9d9b451..2e0c62e 100644 --- a/manual/creature.texi +++ b/manual/creature.texi @@ -71,7 +71,7 @@ included as well as the @w{ISO C}, POSIX.1, POSIX.2, and X/Open material. @end defvr @comment (none) -@comment XOPEN +@comment X/Open @defvr Macro _XOPEN_SOURCE @defvrx Macro _XOPEN_SOURCE_EXTENDED If you define this macro, functionality described in the X/Open @@ -91,11 +91,72 @@ all functionality described so far plus some new definitions from the Single Unix specification, @w{version 2}. @end defvr +@comment (NONE) +@comment X/Open +@defvr Macro _LARGEFILE_SOURCE +If this macro is defined some extra functions are available which +rectify a few shortcomings in all previous standards. More concreten +the functions @code{fseeko} and @code{ftello} are available. Without +these functions the difference between the @w{ISO C} interface +(@code{fseek}, @code{ftell}) and the low-level POSIX interface +(@code{lseek}) would lead to problems. + +This macro was introduced as part of the Large File Support extension (LFS). +@end defvr + +@comment (NONE) +@comment X/Open +@defvar Macro _LARGEFILE64_SOURCE +If you define this macro an additional set of function gets available +which enables to use on @w{32 bit} systems to use files of sizes beyond +the usual limit of 2GB. This interface is not available if the system +does not support files that large. On systems where the natural file +size limit is greater than 2GB (i.e., on @w{64 bit} systems) the new +functions are identical to the replaced functions. + +The new functionality is made available by a new set of types and +functions which replace existing. The names of these new objects +contain @code{64} to indicate the intention, e.g., @code{off_t} +vs. @code{off64_t} and @code{fseeko} vs. @code{fseeko64}. + +This macro was introduced as part of the Large File Support extension +(LFS). It is a transition interface for the time @w{64 bit} offsets are +not generally used (see @code{_FILE_OFFSET_BITS}. +@end defvar + +@comment (NONE) +@comment X/Open +@defvar _FILE_OFFSET_BITS +This macro lets decide which file system interface shall be used, one +replacing the other. While @code{_LARGEFILE64_SOURCE} makes the @w{64 +bit} interface available as an additional interface +@code{_FILE_OFFSET_BITS} allows to use the @w{64 bit} interface to +replace the old interface. + +If @code{_FILE_OFFSET_BITS} is undefined or if it is defined to the +value @code{32} nothing changes. The @w{32 bit} interface is used and +types like @code{off_t} have a size of @w{32 bits} on @w{32 bit} +systems. + +If the macro is defined to the value @code{64} the large file interface +replaces the old interface. I.e., the functions are not made available +under different names as @code{_LARGEFILE64_SOURCE} does. Instead the +old function names now reference the new functions, e.g., a call to +@code{fseeko} now indeed calls @code{fseeko64}. + +This macro should only be selected if the system provides mechanisms for +handling large files. On @w{64 bit} systems this macro has no effect +since the @code{*64} functions are identical to the normal functions. + +This macro was introduced as part of the Large File Support extension +(LFS). +@end defvar + @comment (none) @comment GNU @defvr Macro _GNU_SOURCE If you define this macro, everything is included: @w{ISO C}, POSIX.1, -POSIX.2, BSD, SVID, X/Open, and GNU extensions. In the cases where +POSIX.2, BSD, SVID, X/Open, LFS, and GNU extensions. In the cases where POSIX.1 conflicts with BSD, the POSIX definitions take precedence. If you want to get the full effect of @code{_GNU_SOURCE} but make the |