'\" 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 strndup 3 2026-08-17 "Linux man-pages 6.19"
.SH NAME
strndup \- nonstring duplicate-into-string
.SH LIBRARY
Standard C library
.RI ( libc ,\~ \-lc )
.SH SYNOPSIS
.nf
.BR #include\~<string.h> "  // see memory.h(3head)"
.P
.BR "char *strndup(" "size_t n;"
.BI "              const char " strn [ n "], size_t " n );
.fi
.P
.RS -4
Feature Test Macro Requirements for glibc (see
.BR feature_test_macros (7)):
.RE
.P
.BR strndup ():
.nf
    Since glibc 2.10:
        _POSIX_C_SOURCE >= 200809L
    Before glibc 2.10:
        _GNU_SOURCE
.fi
.SH DESCRIPTION
This function
duplicates at most
.I n
nonnull characters
from the array pointed to by
.IR strn ,
followed by a null character,
into new memory obtained with
.BR malloc (3).
.SH RETURN VALUE
On success, the
.BR strndup ()
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 strndup ()
T}	Thread safety	MT-Safe
.TE
.SH STANDARDS
POSIX.1-2008.
.SH HISTORY
POSIX.1-2008.
.SH SEE ALSO
.BR memory.h (3head),
.BR malloc (3),
.BR strndupa (3)