freebsd-nq/lib/libc/gen/basename.3

.\" $OpenBSD: basename.3,v 1.20 2007/05/31 19:19:28 jmc Exp $
.\"
.\" Copyright (c) 1997 Todd C. Miller <Todd.Miller@courtesan.com>
.\"
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.\" $FreeBSD$
.\"
.Dd July 29, 2016
.Dt BASENAME 3
.Os
.Sh NAME
.Nm basename
.Nd extract the base portion of a pathname
.Sh SYNOPSIS
.In libgen.h
.Ft char *
.Fn basename "char *path"
.Ft char *
.Fn basename_r "const char *path" "char *bname"
.Sh DESCRIPTION
The
.Fn basename
function returns the last component from the pathname pointed to by
.Fa path ,
deleting any trailing
.Sq \&/
characters.
If
.Fa path
consists entirely of
.Sq \&/
characters, a pointer to the string
.Qq \&/
is returned.
If
.Fa path
is a null pointer or the empty string, a pointer to the string
.Qq \&.
is returned.
.Pp
The
.Fn basename_r
variation accepts a buffer of at least
.Dv MAXPATHLEN
bytes in which to store the resulting component.
.Sh IMPLEMENTATION NOTES
The
.Fn basename
function
returns a pointer to internal storage space allocated on the first call
that will be overwritten
by subsequent calls.
.Pp
Other vendor implementations of
.Fn basename
may store their result in the input buffer,
making it safe to use in multithreaded applications.
Future versions of
.Fx
will follow this approach as well.
.Fn basename_r
will then become obsolete.
.Sh RETURN VALUES
On successful completion,
.Fn basename
and
.Fn basename_r
return pointers to the last component of
.Fa path .
.Pp
If they fail, a null pointer is returned and the global variable
.Va errno
is set to indicate the error.
.Sh ERRORS
The following error codes may be set in
.Va errno :
.Bl -tag -width Er
.It Bq Er ENAMETOOLONG
The path component to be returned was larger than
.Dv MAXPATHLEN .
.El
.Sh SEE ALSO
.Xr basename 1 ,
.Xr dirname 1 ,
.Xr dirname 3
.Sh STANDARDS
The
.Fn basename
function conforms to
.St -xpg4.2 .
.Sh HISTORY
The
.Fn basename
function first appeared in
.Ox 2.2
and
.Fx 4.2 .
.Sh AUTHORS
.An Todd C. Miller
.Sh CAVEATS
.Fn basename
returns a pointer to internal static storage space that will be overwritten
by subsequent calls.
.Pp
Other vendor implementations of
.Fn basename
may modify the contents of the string passed to
.Fn basename ;
this should be taken into account when writing code which calls this function
if portability is desired.