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

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

SYNOPSIS
       #include	<dirent.h>

       int scandir(const char *dir, struct dirent ***namelist,
	      int(*select)(const struct	dirent *),
	      int(*compar)(const struct	dirent **, const struct	dirent **));

       int alphasort(const void	*a, const void *b);
       int versionsort(const void *a, const void *b);

DESCRIPTION
       The  scandir()  function	 scans	the directory dir, calling select() on
       each directory entry.  Entries for which	select() returns non-zero  are
       stored in strings allocated via malloc(), sorted	using qsort() with the
       comparison function compar(), and collected in array namelist which  is
       allocated via malloc().	If select 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.

RETURN VALUE
       The scandir() function returns the number of directory entries selected
       or -1 if	an error occurs.

       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
       ENOMEM Insufficient memory to complete the operation.

CONFORMING TO
       None of these functions is in POSIX.  The functions scandir()  and  al-
       phasort()  are  from BSD	4.3, and have been available under Linux since
       libc4.  Libc4 and libc5 use the more precise prototype

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

       but glibc 2.0 returns to	the imprecise BSD prototype.

       The function versionsort() is a GNU extension,  available  since	 glibc
       2.1.   Since  glibc  2.1, alphasort() calls strcoll(3); earlier it used
       strcmp(3).

EXAMPLE
       /* print	files in current directory in reverse order */
       #include	<dirent.h>
       main(){
	   struct dirent **namelist;
	   int n;

	   n = scandir(".", &namelist, 0, 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)

GNU				  2001-12-26			    SCANDIR(3)

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

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