1.\" Copyright (c) 1990, 1991, 1993 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. 12.\" 3. 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.\" 28.\" from: @(#)strdup.3 8.1 (Berkeley) 6/9/93 29.\" $NetBSD: strdup.3,v 1.18 2009/01/29 10:15:39 wiz Exp $ 30.\" 31.Dd January 28, 2009 32.Dt STRDUP 3 33.Os 34.Sh NAME 35.Nm strdup , 36.Nm strndup 37.Nd save a copy of a string 38.Sh LIBRARY 39.Lb libc 40.Sh SYNOPSIS 41.In string.h 42.Ft char * 43.Fn strdup "const char *str" 44.Ft char * 45.Fn strndup "const char *str" "size_t len" 46.Sh DESCRIPTION 47The 48.Fn strdup 49function 50allocates sufficient memory for a copy 51of the string 52.Fa str , 53does the copy, and returns a pointer to it. 54The pointer may subsequently be used as an 55argument to the function 56.Xr free 3 . 57.Pp 58If insufficient memory is available, 59.Dv NULL 60is returned. 61.Pp 62The 63.Fn strndup 64function copies at most 65.Fa len 66characters from the string 67.Fa str 68always 69.Dv NUL 70terminating the copied string. 71.Sh EXAMPLES 72The following will point 73.Va p 74to an allocated area of memory containing the nul-terminated string 75.Qq foobar : 76.Bd -literal -offset indent 77char *p; 78 79if ((p = strdup("foobar")) == NULL) { 80 fprintf(stderr, "Out of memory.\en"); 81 exit(1); 82} 83.Ed 84.Sh ERRORS 85The 86.Fn strdup 87function may fail and set the external variable 88.Va errno 89for any of the errors specified for the library function 90.Xr malloc 3 . 91.Sh SEE ALSO 92.Xr free 3 , 93.Xr malloc 3 , 94.Xr strcpy 3 , 95.Xr strlen 3 96.Sh STANDARDS 97The 98.Fn strdup 99function conforms to 100.St -p1003.1-2001 . 101.Sh HISTORY 102The 103.Fn strdup 104function first appeared in 105.Bx 4.4 . 106The 107.Fn strndup 108function was added in 109.Nx 4.0 . 110