.\" $OpenBSD: scandir.3,v 1.11 2012/03/24 18:52:42 guenther Exp $ .\" .\" Copyright (c) 1983, 1991, 1993 .\" The Regents of the University of California. All rights reserved. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" 3. Neither the name of the University nor the names of its contributors .\" may be used to endorse or promote products derived from this software .\" without specific prior written permission. .\" .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE .\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" .Dd $Mdocdate: March 24 2012 $ .Dt SCANDIR 3 .Os .Sh NAME .Nm scandir , .Nm alphasort .Nd scan a directory .Sh SYNOPSIS .Fd #include .Fd #include .Ft int .Fn scandir "const char *dirname" "struct dirent ***namelist" "int \*(lp*select\*(rp\*(lpstruct dirent *\*(rp" "int \*(lp*compar\*(rp\*(lpconst struct dirent **, const struct dirent **\*(rp" .Ft int .Fn alphasort "const struct dirent **d1" "const struct dirent **d2" .Sh DESCRIPTION The .Fn scandir function reads the directory .Fa dirname and builds an array of pointers to directory entries using .Xr malloc 3 . It returns the number of entries in the array. A pointer to the array of directory entries is stored in the location referenced by .Fa namelist . .Pp The .Fa select parameter is a pointer to a user-supplied subroutine which is called by .Fn scandir to select which entries are to be included in the array. The select routine is passed a pointer to a directory entry and should return a non-zero value if the directory entry is to be included in the array. If .Fa select is .Dv NULL , then all directory entries will be included. .Pp The .Fa compar parameter is a pointer to a user-supplied subroutine which is passed to .Xr qsort 3 to sort the completed array. If this pointer is .Dv NULL , the array is not sorted. .Pp The .Fn alphasort function is a routine which can be used for the .Fa compar parameter to sort the array alphabetically. .Pp The memory allocated for the array can be deallocated with .Xr free 3 , by freeing each pointer in the array and then the array itself. .Sh DIAGNOSTICS Returns \-1 if the directory cannot be opened for reading or if .Xr malloc 3 cannot allocate enough memory to hold all the data structures. .Sh SEE ALSO .Xr directory 3 , .Xr malloc 3 , .Xr qsort 3 , .Xr dir 5 .Sh STANDARDS The .Fn scandir and .Fn alphasort functions conform to .St -p1003.1-2008 . .Sh HISTORY The .Fn scandir and .Fn alphasort functions appeared in .Bx 4.2 . .Pp The argument types for .Fn alphasort and for the .Fn compar argument to .Fn scandir were originally .Vt "void *" , then changed to .Vt "const void *" , and then finally changed by .St -p1003.1-2008 to their current form of .Vt "const struct dirent **" .