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Man page of STRDUP
STRDUP
Section: Linux Programmer's Manual (3)
Updated: 2016-03-15
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NAME
strdup, strndup, strdupa, strndupa - duplicate a string
SYNOPSIS
#include <string.h>
char *strdup(const char *s);
char *strndup(const char *s, size_t n);
char *strdupa(const char *s);
char *strndupa(const char *s, size_t n);
Feature Test Macro Requirements for glibc (see
feature_test_macros(7)):
strdup():
-
_XOPEN_SOURCE >= 500
|| /* Since glibc 2.12: */ _POSIX_C_SOURCE >= 200809L
|| /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
strndup():
-
- Since glibc 2.10:
-
_POSIX_C_SOURCE >= 200809L
- Before glibc 2.10:
-
_GNU_SOURCE
strdupa(),
strndupa():
_GNU_SOURCE
DESCRIPTION
The
strdup()
function returns a pointer to a new string which
is a duplicate of the string
s.
Memory for the new string is
obtained with
malloc(3),
and can be freed with
free(3).
The
strndup()
function is similar, but copies at most
n
bytes.
If
s
is longer than
n,
only
n
bytes are copied, and a terminating null byte ('\0') is added.
strdupa()
and
strndupa()
are similar, but use
alloca(3)
to allocate the buffer.
They are available only when using the GNU
GCC suite, and suffer from the same limitations described in
alloca(3).
RETURN VALUE
On success, the
strdup()
function returns a pointer to the duplicated
string.
It returns NULL if insufficient memory was available, with
errno
set to indicate the cause of the error.
ERRORS
- ENOMEM
-
Insufficient memory available to allocate duplicate string.
ATTRIBUTES
For an explanation of the terms used in this section, see
attributes(7).
| Interface | Attribute | Value
|
strdup(),
strndup(),
strdupa(),
strndupa()
| Thread safety | MT-Safe
|
CONFORMING TO
strdup()
conforms to SVr4, 4.3BSD, POSIX.1-2001.
strndup()
conforms to POSIX.1-2008.
strdupa()
and
strndupa()
are GNU extensions.
SEE ALSO
alloca(3),
calloc(3),
free(3),
malloc(3),
realloc(3),
string(3),
wcsdup(3)
COLOPHON
This page is part of release 4.09 of the Linux
man-pages
project.
A description of the project,
information about reporting bugs,
and the latest version of this page,
can be found at
https://www.kernel.org/doc/man-pages/.
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- RETURN VALUE
-
- ERRORS
-
- ATTRIBUTES
-
- CONFORMING TO
-
- SEE ALSO
-
- COLOPHON
-
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