1998-03-21 09:15  Ulrich Drepper  <drepper@cygnus.com>

	* manual/filesys.texi (Scanning Directory Content): Add description
	of 64 bits scandir function and friends.
This commit is contained in:
Ulrich Drepper 1998-03-21 09:19:12 +00:00
parent dfae7a5920
commit 5679cdb6e2
2 changed files with 60 additions and 2 deletions

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@ -1,3 +1,8 @@
1998-03-21 09:15 Ulrich Drepper <drepper@cygnus.com>
* manual/filesys.texi (Scanning Directory Content): Add description
of 64 bits scandir function and friends.
1998-03-20 Ulrich Drepper <drepper@cygnus.com>
* glibcbug.in: Use mktemp to generate unique file name for

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@ -447,7 +447,9 @@ A higher-level interface to the directory handling functions is the
entries in a directory, possibly sort them and get as the result a list
of names.
@deftypefun int scandir (const char *@var{dir}, struct dirent ***@var{namelist}, int (*@var{selector}) (struct dirent *), int (*@var{cmp}) (const void *, const void *))
@comment dirent.h
@comment BSD/SVID
@deftypefun int scandir (const char *@var{dir}, struct dirent ***@var{namelist}, int (*@var{selector}) (const struct dirent *), int (*@var{cmp}) (const void *, const void *))
The @code{scandir} function scans the contents of the directory selected
by @var{dir}. The result in @var{namelist} is an array of pointers to
@ -475,8 +477,10 @@ a pointer to a sorting function. For the convenience of the programmer
the GNU C library contains implementations of functions which are very
helpful for this purpose.
@comment dirent.h
@comment BSD/SVID
@deftypefun int alphasort (const void *@var{a}, const void *@var{b})
The @code{alphasort} function behaves like the @code{strcmp} function
The @code{alphasort} function behaves like the @code{strcoll} function
(@pxref{String/Array Comparison}). The difference is that the arguments
are not string pointers but instead they are of type
@code{struct dirent **}.
@ -485,11 +489,60 @@ Return value of is less than, equal to, or greater than zero depending
on the order of the two entries @var{a} and @var{b}.
@end deftypefun
@comment dirent.h
@comment GNU
@deftypefun int versionsort (const void *@var{a}, const void *@var{b})
The @code{versionsort} function is like @code{alphasort}, excepted that it
uses the @code{strverscmp} function internally.
@end deftypefun
If the filesystem supports large files we cannot use the @code{scandir}
anymore since the @code{dirent} structure might not able to contain all
the information. The LFS provides the new type @w{@code{struct
dirent64}}. To use this we need a new function.
@comment dirent.h
@comment GNU
@deftypefun int scandir64 (const char *@var{dir}, struct dirent64 ***@var{namelist}, int (*@var{selector}) (const struct dirent64 *), int (*@var{cmp}) (const void *, const void *))
The @code{scandir64} function works like the @code{scandir} function
only that the directory entries it returns are described by elements of
type @w{@code{struct dirent64}}. The function pointed to by
@var{selector} is again used to select the wanted entries only that
@var{selector} now must point to a function which takes a
@w{@code{struct dirent64 *} parameter.
The @var{cmp} now must be a function which expects its two arguments to
be of type @code{struct dirent64 **}.
@end deftypefun
As just said the function expected as the fourth is different from the
function expected in @code{scandir}. Therefore we cannot use the
@code{alphasort} and @code{versionsort} functions anymore. Instead we
have two similar functions available.
@comment dirent.h
@comment GNU
@deftypefun int alphasort64 (const void *@var{a}, const void *@var{b})
The @code{alphasort64} function behaves like the @code{strcoll} function
(@pxref{String/Array Comparison}). The difference is that the arguments
are not string pointers but instead they are of type
@code{struct dirent64 **}.
Return value of is less than, equal to, or greater than zero depending
on the order of the two entries @var{a} and @var{b}.
@end deftypefun
@comment dirent.h
@comment GNU
@deftypefun int versionsort64 (const void *@var{a}, const void *@var{b})
The @code{versionsort64} function is like @code{alphasort64}, excepted that it
uses the @code{strverscmp} function internally.
@end deftypefun
It is important not to mix the use of @code{scandir} and the 64 bits
comparison functions or vice versa. There are systems on which this
work but on others it will fail miserably.
@node Simple Directory Lister Mark II
@subsection Simple Program to List a Directory, Mark II