strdup(3) - Linux manual page (original) (raw)
strdup(3) Library Functions Manual strdup(3)
NAME top
strdup, strndup, strdupa, strndupa - duplicate a stringLIBRARY top
Standard C library (_libc_, _-lc_)SYNOPSIS top
**#include <string.h>**
**char *strdup(const char ***_s_**);**
**char *strndup(const char** _s_**[.**_n_**], size_t** _n_**);**
**char *strdupa(const char ***_s_**);**
**char *strndupa(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_SOURCEDESCRIPTION top
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)](../man3/malloc.3.html), and can be freed with [free(3)](../man3/free.3.html).
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)](../man3/alloca.3.html) to
allocate the buffer.RETURN VALUE top
On success, the **strdup**() function returns a pointer to the
duplicated string. It returns NULL if insufficient memory was
available, with _[errno](../man3/errno.3.html)_ set to indicate the error.ERRORS top
**ENOMEM** Insufficient memory available to allocate duplicate string.ATTRIBUTES top
For an explanation of the terms used in this section, see
[attributes(7)](../man7/attributes.7.html).
┌──────────────────────────────────────┬───────────────┬─────────┐
│ **Interface** │ **Attribute** │ **Value** │
├──────────────────────────────────────┼───────────────┼─────────┤
│ **strdup**(), **strndup**(), **strdupa**(), │ Thread safety │ MT-Safe │
│ **strndupa**() │ │ │
└──────────────────────────────────────┴───────────────┴─────────┘STANDARDS top
**strdup**()
**strndup**()
POSIX.1-2008.
**strdupa**()
**strndupa**()
GNU.HISTORY top
**strdup**()
SVr4, 4.3BSD-Reno, POSIX.1-2001.
**strndup**()
POSIX.1-2008.
**strdupa**()
**strndupa**()
GNU.SEE ALSO top
[alloca(3)](../man3/alloca.3.html), [calloc(3)](../man3/calloc.3.html), [free(3)](../man3/free.3.html), [malloc(3)](../man3/malloc.3.html), [realloc(3)](../man3/realloc.3.html), [string(3)](../man3/string.3.html),
[wcsdup(3)](../man3/wcsdup.3.html)COLOPHON top
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man-pages@man7.orgLinux man-pages 6.10 2024-07-23 strdup(3)
Pages that refer to this page:alloca(3), ldap_memory(3), pmdadaemon(3), pmdafetch(3), pmfault(3), pmtraversepmns(3), strcpy(3), string(3), wcsdup(3), string_copying(7)