[apple/libc.git] / string / FreeBSD / strdup.3

.\" Copyright (c) 1990, 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.
.\" 4. 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.
.\"
.\"     @(#)strdup.3	8.1 (Berkeley) 6/9/93
.\" $FreeBSD: src/lib/libc/string/strdup.3,v 1.15 2009/04/07 13:42:53 trasz Exp $
.\"
.Dd December 5, 2008
.Dt STRDUP 3
.Os
.Sh NAME
.Nm strdup ,
.Nm strndup
.Nd save a copy of a string
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In string.h
.Ft char *
.Fo strdup
.Fa "const char *s1"
.Fc
.Ft char *
.Fo strndup
.Fa "const char *s1"
.Fa "size_t n"
.Fc
.Sh DESCRIPTION
The
.Fn strdup
function
allocates sufficient memory for a copy
of the string
.Fa s1 ,
does the copy, and returns a pointer to it.
The pointer may subsequently be used as an
argument to the function
.Xr free 3 .
.Pp
If insufficient memory is available, NULL is returned and
.Va errno
is set to
.Er ENOMEM .
.Pp
The
.Fn strndup
function copies at most
.Fa n
characters from the string
.Fa s1
always
.Dv NUL
terminating the copied string.
.Sh SEE ALSO
.Xr free 3 ,
.Xr malloc 3
.Sh HISTORY
The
.Fn strdup
function first appeared in
.Bx 4.4 .
The
.Fn strndup
function was added in
.Fx 7.2 .
Commit	Line	Data
5b2abdfb	1	.\" Copyright (c) 1990, 1991, 1993
e9ce8d39 A	2	.\" The Regents of the University of California. All rights reserved.
	3	.\"
	4	.\" Redistribution and use in source and binary forms, with or without
	5	.\" modification, are permitted provided that the following conditions
	6	.\" are met:
	7	.\" 1. Redistributions of source code must retain the above copyright
	8	.\" notice, this list of conditions and the following disclaimer.
	9	.\" 2. Redistributions in binary form must reproduce the above copyright
	10	.\" notice, this list of conditions and the following disclaimer in the
	11	.\" documentation and/or other materials provided with the distribution.
e9ce8d39 A	12	.\" 4. Neither the name of the University nor the names of its contributors
	13	.\" may be used to endorse or promote products derived from this software
	14	.\" without specific prior written permission.
	15	.\"
	16	.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	17	.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	18	.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	19	.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	20	.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	21	.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	22	.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	23	.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	24	.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	25	.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	26	.\" SUCH DAMAGE.
	27	.\"
5b2abdfb	28	.\" @(#)strdup.3 8.1 (Berkeley) 6/9/93
1f2f436a	29	.\" $FreeBSD: src/lib/libc/string/strdup.3,v 1.15 2009/04/07 13:42:53 trasz Exp $
e9ce8d39	30	.\"
1f2f436a	31	.Dd December 5, 2008
5b2abdfb	32	.Dt STRDUP 3
e9ce8d39 A	33	.Os
e9ce8d39 A	34	.Sh NAME
1f2f436a A	35	.Nm strdup ,
1f2f436a A	36	.Nm strndup
5b2abdfb	37	.Nd save a copy of a string
e9ce8d39 A	38	.Sh LIBRARY
	39	.Lb libc
	40	.Sh SYNOPSIS
5b2abdfb A	41	.In string.h
5b2abdfb A	42	.Ft char *
ad3c9f2a A	43	.Fo strdup
	44	.Fa "const char *s1"
	45	.Fc
1f2f436a	46	.Ft char *
ad3c9f2a A	47	.Fo strndup
	48	.Fa "const char *s1"
	49	.Fa "size_t n"
	50	.Fc
e9ce8d39 A	51	.Sh DESCRIPTION
e9ce8d39 A	52	The
5b2abdfb A	53	.Fn strdup
	54	function
	55	allocates sufficient memory for a copy
	56	of the string
ad3c9f2a	57	.Fa s1 ,
5b2abdfb A	58	does the copy, and returns a pointer to it.
	59	The pointer may subsequently be used as an
	60	argument to the function
	61	.Xr free 3 .
	62	.Pp
	63	If insufficient memory is available, NULL is returned and
	64	.Va errno
	65	is set to
	66	.Er ENOMEM .
1f2f436a A	67	.Pp
	68	The
	69	.Fn strndup
	70	function copies at most
ad3c9f2a	71	.Fa n
1f2f436a	72	characters from the string
ad3c9f2a	73	.Fa s1
1f2f436a A	74	always
	75	.Dv NUL
	76	terminating the copied string.
e9ce8d39	77	.Sh SEE ALSO
5b2abdfb	78	.Xr free 3 ,
ad3c9f2a	79	.Xr malloc 3
e9ce8d39 A	80	.Sh HISTORY
e9ce8d39 A	81	The
5b2abdfb	82	.Fn strdup
e9ce8d39 A	83	function first appeared in
e9ce8d39 A	84	.Bx 4.4 .
1f2f436a A	85	The
	86	.Fn strndup
	87	function was added in
	88	.Fx 7.2 .