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SCANDIR(3)		   Linux Programmer's Manual		    SCANDIR(3)

NAME
       scandir,	 scandirat,  alphasort,	 versionsort  -	 scan  a directory for
       matching	entries

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  se-
       lected.

       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()).

       If dirp is absolute, then dirfd is ignored.

       See openat(2) for an explanation	of the need for	scandirat().

RETURN VALUE
       The scandir() function returns the  number  of  directory  entries  se-
       lected.	On error, -1 is	returned, with errno set to indicate the cause
       of the error.

       The alphasort() and versionsort()  functions  return  an	 integer  less
       than,  equal  to, or greater than zero if the first argument is consid-
       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.

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).

EXAMPLE
       #define _SVID_SOURCE
       /* print	files in current directory in reverse order */
       #include	<dirent.h>

       int
       main(void)
       {
	   struct dirent **namelist;
	   int n;

	   n = scandir(".", &namelist, NULL, alphasort);
	   if (n < 0)
	       perror("scandir");
	   else	{
	       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 3.74 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				  2014-05-28			    SCANDIR(3)

NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | VERSIONS | CONFORMING TO | NOTES | EXAMPLE | SEE ALSO | COLOPHON

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