gen/FreeBSD/scandir.3

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  28 .\"     @(#)scandir.3   8.1 (Berkeley) 6/4/93
  29 .\" $FreeBSD: src/lib/libc/gen/scandir.3,v 1.9 2007/01/09 00:27:55 imp Exp $
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  31 .Dd June 4, 1993
  32 .Dt SCANDIR 3
  33 .Os
  34 .Sh NAME
  35 .Nm scandir ,
  36 .Nm alphasort
  37 .Nd scan a directory
  38 .Sh LIBRARY
  39 .Lb libc
  40 .Sh SYNOPSIS
  41 .In sys/types.h
  42 .In dirent.h
  43 .Ft int
  44 .Fn scandir "const char *dirname" "struct dirent ***namelist" "int \\*(lp*select\\*(rp\\*(lpstruct dirent *\\*(rp" "int \\*(lp*compar\\*(rp\\*(lpconst void *, const void *\\*(rp"
  45 .Ft int
  46 .Fn alphasort "const void *d1" "const void *d2"
  47 .Sh DESCRIPTION
  48 The
  49 .Fn scandir
  50 function
  51 reads the directory
  52 .Fa dirname
  53 and builds an array of pointers to directory
  54 entries using
  55 .Xr malloc 3 .
  56 It returns the number of entries in the array.
  57 A pointer to the array of directory entries is stored in the location
  58 referenced by
  59 .Fa namelist .
  60 .Pp
  61 The
  62 .Fa select
  63 argument is a pointer to a user supplied subroutine which is called by
  64 .Fn scandir
  65 to select which entries are to be included in the array.
  66 The select routine is passed a
  67 pointer to a directory entry and should return a non-zero
  68 value if the directory entry is to be included in the array.
  69 If
  70 .Fa select
  71 is null, then all the directory entries will be included.
  72 .Pp
  73 The
  74 .Fa compar
  75 argument is a pointer to a user supplied subroutine which is passed to
  76 .Xr qsort 3
  77 to sort the completed array.
  78 If this pointer is null, the array is not sorted.
  79 .Pp
  80 The
  81 .Fn alphasort
  82 function
  83 is a routine which can be used for the
  84 .Fa compar
  85 argument to sort the array alphabetically.
  86 .Pp
  87 The memory allocated for the array can be deallocated with
  88 .Xr free 3 ,
  89 by freeing each pointer in the array and then the array itself.
  90 .Sh DIAGNOSTICS
  91 Returns \-1 if the directory cannot be opened for reading or if
  92 .Xr malloc 3
  93 cannot allocate enough memory to hold all the data structures.
  94 .Sh SEE ALSO
  95 .Xr directory 3 ,
  96 .Xr malloc 3 ,
  97 .Xr qsort 3 ,
  98 .Xr dir 5
  99 .Sh HISTORY
 100 The
 101 .Fn scandir
 102 and
 103 .Fn alphasort
 104 functions appeared in
 105 .Bx 4.2 .