diff options
Diffstat (limited to 'manual')
| -rw-r--r-- | manual/filesys.texi | 57 |
1 files changed, 55 insertions, 2 deletions
diff --git a/manual/filesys.texi b/manual/filesys.texi index 6e4baa5673..8a91639a4e 100644 --- a/manual/filesys.texi +++ b/manual/filesys.texi @@ -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 |