alphasort

SYNOPSIS
       #include <dirent.h>

       int scandir(const char *dirp, struct dirent ***namelist,
              int (*filter)(const struct dirent *),
              int (*compar)(const struct dirent **, const struct dirent **));

       int alphasort(const struct dirent **a, const struct dirent **b);

       int versionsort(const struct dirent **a, const struct dirent **b);

       #include <fcntl.h>          /* Definition of AT_* constants */
       #include <dirent.h>

       int scandirat(int dirfd, const char *dirp, struct dirent ***namelist,
              int (*filter)(const struct dirent *),
              int (*compar)(const struct dirent **, const struct dirent **));

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       scandir(), alphasort():
           _BSD_SOURCE || _SVID_SOURCE
           || /* Since glibc 2.10: */
               (_POSIX_C_SOURCE >= 200809L || _XOPEN_SOURCE >= 700)

       versionsort(): _GNU_SOURCE

       scandirat(): _GNU_SOURCE

DESCRIPTION
       The scandir() function scans the directory dirp,  calling  filter()  on
       each  directory  entry.  Entries for which filter() returns nonzero are
       stored in strings allocated via malloc(3), sorted using  qsort(3)  with
       the comparison function compar(), and collected in array namelist which
       is allocated via  malloc(3).   If  filter  is  NULL,  all  entries  are
       selected.

       The alphasort() and versionsort() functions can be used as the compari-
       son function compar().  The former sorts directory entries  using  str-
       coll(3), the latter using strverscmp(3) on the strings (*a)->d_name and
       (*b)->d_name.

   scandirat()
       The scandirat() function operates in exactly the same way as scandir(),
       except for the differences described here.

       If the pathname given in dirp is relative, then it is interpreted rela-
       tive to the directory referred to by the file descriptor dirfd  (rather
       than  relative to the current working directory of the calling process,
       as is done by scandir() for a relative pathname).

       If dirp is relative and dirfd is the special value AT_FDCWD, then  dirp
       is interpreted relative to the current working directory of the calling
       process (like scandir()).
       ered to be respectively less than, equal to, or greater than  the  sec-
       ond.

ERRORS
       ENOENT The path in dirp does not exist.

       ENOMEM Insufficient memory to complete the operation.

       ENOTDIR
              The path in dirp is not a directory.

       The following additional errors can occur for scandirat():

       EBADF  dirfd is not a valid file descriptor.

       ENOTDIR
              dirp is a relative path and dirfd is a file descriptor referring
              to a file other than a directory.

VERSIONS
       versionsort() was added to glibc in version 2.1.

       scandirat() was added to glibc in version 2.15.

ATTRIBUTES
       For  an  explanation  of  the  terms  used   in   this   section,   see
       attributes(7).

       +---------------------------+---------------+----------------+
       |Interface                  | Attribute     | Value          |
       +---------------------------+---------------+----------------+
       |scandir(), scandirat()     | Thread safety | MT-Safe        |
       +---------------------------+---------------+----------------+
       |alphasort(), versionsort() | Thread safety | MT-Safe locale |
       +---------------------------+---------------+----------------+

CONFORMING TO
       alphasort(), scandir(): 4.3BSD, POSIX.1-2008.

       versionsort() and scandirat() are GNU extensions.

NOTES
       Since  glibc  2.1,  alphasort()  calls strcoll(3); earlier it used str-
       cmp(3).

       Before glibc 2.10, the two arguments of alphasort()  and  versionsort()
       were  typed  as  const  void *.   When  alphasort() was standardized in
       POSIX.1-2008, the argument type was specified as  the  type-safe  const
       struct  dirent **, and glibc 2.10 changed the definition of alphasort()
       (and the nonstandard versionsort()) to match the standard.

EXAMPLE
       #define _SVID_SOURCE
       /* print files in current directory in reverse order */
               while (n--) {
                   printf("%s\n", namelist[n]->d_name);
                   free(namelist[n]);
               }
               free(namelist);
           }
       }

SEE ALSO
       closedir(3),   fnmatch(3),   opendir(3),   readdir(3),    rewinddir(3),
       seekdir(3), strcmp(3), strcoll(3), strverscmp(3), telldir(3)

COLOPHON
       This  page  is  part of release 4.04 of the Linux man-pages project.  A
       description of the project, information about reporting bugs,  and  the
       latest     version     of     this    page,    can    be    found    at
       http://www.kernel.org/doc/man-pages/.

GNU                               2015-04-19                        SCANDIR(3)
Man Pages Copyright Respective Owners. Site Copyright (C) 1994 - 2019 Hurricane Electric. All Rights Reserved.