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.\" @(#)strdup.3 8.1 (Berkeley) 6/9/93 29.\" 30.Dd May 5, 2020 31.Dt STRDUP 3 32.Os 33.Sh NAME 34.Nm strdup , 35.Nm strndup 36.Nd save a copy of a string 37.Sh LIBRARY 38.Lb libc 39.Sh SYNOPSIS 40.In string.h 41.Ft char * 42.Fn strdup "const char *str" 43.Ft char * 44.Fn strndup "const char *str" "size_t len" 45.Sh DESCRIPTION 46The 47.Fn strdup 48function 49allocates sufficient memory for a copy 50of the string 51.Fa str , 52does the copy, and returns a pointer to it. 53The memory is allocated with 54.Xr malloc 3 55and should be released with 56.Xr free 3 57when no longer needed. 58.Pp 59The 60.Fn strndup 61function copies at most 62.Fa len 63characters from the string 64.Fa str 65always 66.Dv NUL 67terminating the copied string. 68.Sh RETURN VALUES 69If insufficient memory is available, NULL is returned and 70.Va errno 71is set to 72.Er ENOMEM . 73Otherwise, the 74.Fn strdup 75family of functions return a pointer to the copied string. 76.Sh SEE ALSO 77.Xr free 3 , 78.Xr malloc 3 , 79.Xr wcsdup 3 80.Sh STANDARDS 81The 82.Fn strdup 83function is specified by 84.St -p1003.1-2001 . 85The 86.Fn strndup 87function is specified by 88.St -p1003.1-2008 . 89.Sh HISTORY 90The 91.Fn strdup 92function first appeared in 93.Bx 4.3 Reno . 94The 95.Fn strndup 96function was added in 97.Fx 7.2 . 98