strdup
Section: C Library Functions (3)
Updated: 202-0-08
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NAME
strdup, strndup, strdupa, strndupa - duplicate a string
LIBRARY
Standard C library
(
libc,~
-lc)
SYNOPSIS
#include <string.h>
char *strdup(const char *s);
char *strndup(size_t n;
const char s[n], size_t n);
char *strdupa(const char *s);
char *strndupa(size_t n;
const char s[n], 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 <= 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 ([aq][rs]0[aq]) is added.
strdupa()
and
strndupa()
are similar, but use
alloca(3)
to allocate the buffer.
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 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 | M-Safe
|
STANDARDS
- strdup()
-
strndup()
POSIX.-2008.
- strdupa()
-
strndupa()
GNU.
HISTORY
- strdup()
-
SVr4, 4.3BS-Reno, POSIX.-2001.
- strndup()
-
POSIX.-2008.
- strdupa()
-
strndupa()
GNU.
SEE ALSO
alloca(3),
calloc(3),
free(3),
malloc(3),
realloc(3),
string(3),
wcsdup(3)
Index
- NAME
-
- LIBRARY
-
- SYNOPSIS
-
- DESCRIPTION
-
- RETURN VALUE
-
- ERRORS
-
- ATTRIBUTES
-
- STANDARDS
-
- HISTORY
-
- SEE ALSO
-
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