'\" t
.\" Copyright 1993, David Metcalfe <david@prism.demon.co.uk>
.\" Copyright, the authors of the Linux man-pages project
.\"
.\" SPDX-License-Identifier: Linux-man-pages-copyleft
.\"
.TH strdup 3 2026-08-10 "Linux man-pages 6.19"
.SH NAME
strdup \- string duplicate
.SH LIBRARY
Standard C library
.RI ( libc ,\~ \-lc )
.SH SYNOPSIS
.nf
.B #include <string.h>
.P
.BI "char *strdup(const char *" s );
.fi
.P
.RS -4
Feature Test Macro Requirements for glibc (see
.BR feature_test_macros (7)):
.RE
.P
.BR strdup ():
.nf
    _XOPEN_SOURCE >= 500
.\"    || _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED
        || /* Since glibc 2.12: */ _POSIX_C_SOURCE >= 200809L
        || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
.fi
.SH DESCRIPTION
The
.BR strdup ()
function returns a pointer to a new string which
is a duplicate of the string
.IR s .
Memory for the new string is
obtained with
.BR malloc (3),
and can be freed with
.BR free (3).
.SH RETURN VALUE
On success, the
.BR strdup ()
function returns a pointer to the duplicated
string.
It returns NULL if insufficient memory was available, with
.I errno
set to indicate the error.
.SH ERRORS
See
.BR malloc (3).
.SH ATTRIBUTES
For an explanation of the terms used in this section, see
.BR attributes (7).
.TS
allbox;
lbx lb lb
l l l.
Interface	Attribute	Value
T{
.na
.nh
.BR strdup ()
T}	Thread safety	MT-Safe
.TE
.SH STANDARDS
POSIX.1-2008.
.SH HISTORY
SVr4, 4.3BSD-Reno, POSIX.1-2001.
.SH SEE ALSO
.BR malloc (3),
.BR string (3),
.BR strdupa (3),
.BR wcsdup (3)