gen/FreeBSD/scandir.3

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  32 .\"     @(#)scandir.3   8.1 (Berkeley) 6/4/93
  33 .\" $FreeBSD: src/lib/libc/gen/scandir.3,v 1.8 2002/12/19 09:40:21 ru Exp $
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  35 .Dd June 4, 1993
  36 .Dt SCANDIR 3
  37 .Os
  38 .Sh NAME
  39 .Nm scandir ,
  40 .Nm alphasort
  41 .Nd scan a directory
  42 .Sh LIBRARY
  43 .Lb libc
  44 .Sh SYNOPSIS
  45 .In sys/types.h
  46 .In dirent.h
  47 .Ft int
  48 .Fn scandir "const char *dirname" "struct dirent ***namelist" "int \\*(lp*select\\*(rp\\*(lpstruct dirent *\\*(rp" "int \\*(lp*compar\\*(rp\\*(lpconst void *, const void *\\*(rp"
  49 .Ft int
  50 .Fn alphasort "const void *d1" "const void *d2"
  51 .Sh DESCRIPTION
  52 The
  53 .Fn scandir
  54 function
  55 reads the directory
  56 .Fa dirname
  57 and builds an array of pointers to directory
  58 entries using
  59 .Xr malloc 3 .
  60 It returns the number of entries in the array.
  61 A pointer to the array of directory entries is stored in the location
  62 referenced by
  63 .Fa namelist .
  64 .Pp
  65 The
  66 .Fa select
  67 argument is a pointer to a user supplied subroutine which is called by
  68 .Fn scandir
  69 to select which entries are to be included in the array.
  70 The select routine is passed a
  71 pointer to a directory entry and should return a non-zero
  72 value if the directory entry is to be included in the array.
  73 If
  74 .Fa select
  75 is null, then all the directory entries will be included.
  76 .Pp
  77 The
  78 .Fa compar
  79 argument is a pointer to a user supplied subroutine which is passed to
  80 .Xr qsort 3
  81 to sort the completed array.
  82 If this pointer is null, the array is not sorted.
  83 .Pp
  84 The
  85 .Fn alphasort
  86 function
  87 is a routine which can be used for the
  88 .Fa compar
  89 argument to sort the array alphabetically.
  90 .Pp
  91 The memory allocated for the array can be deallocated with
  92 .Xr free 3 ,
  93 by freeing each pointer in the array and then the array itself.
  94 .Sh DIAGNOSTICS
  95 Returns \-1 if the directory cannot be opened for reading or if
  96 .Xr malloc 3
  97 cannot allocate enough memory to hold all the data structures.
  98 .Sh SEE ALSO
  99 .Xr directory 3 ,
 100 .Xr malloc 3 ,
 101 .Xr qsort 3 ,
 102 .Xr dir 5
 103 .Sh HISTORY
 104 The
 105 .Fn scandir
 106 and
 107 .Fn alphasort
 108 functions appeared in
 109 .Bx 4.2 .