STRDUP(3P) POSIX Programmer's Manual STRDUP(3P)PROLOG
This manual page is part of the POSIX Programmer's Manual. The Linux
implementation of this interface may differ (consult the corresponding
Linux manual page for details of Linux behavior), or the interface may
not be implemented on Linux.
NAME
strdup, strndup — duplicate a specific number of bytes from a string
SYNOPSIS
#include <string.h>
char *strdup(const char *s);
char *strndup(const char *s, size_t size);
DESCRIPTION
The strdup() function shall return a pointer to a new string, which is
a duplicate of the string pointed to by s. The returned pointer can be
passed to free(). A null pointer is returned if the new string cannot
be created.
The strndup() function shall be equivalent to the strdup() function,
duplicating the provided s in a new block of memory allocated as if by
using malloc(), with the exception being that strndup() copies at most
size plus one bytes into the newly allocated memory, terminating the
new string with a NUL character. If the length of s is larger than
size, only size bytes shall be duplicated. If size is larger than the
length of s, all bytes in s shall be copied into the new memory buffer,
including the terminating NUL character. The newly created string shall
always be properly terminated.
RETURN VALUE
The strdup() function shall return a pointer to a new string on suc‐
cess. Otherwise, it shall return a null pointer and set errno to indi‐
cate the error.
Upon successful completion, the strndup() function shall return a
pointer to the newly allocated memory containing the duplicated string.
Otherwise, it shall return a null pointer and set errno to indicate the
error.
ERRORS
These functions shall fail if:
ENOMEM Storage space available is insufficient.
The following sections are informative.
EXAMPLES
None.
APPLICATION USAGE
For functions that allocate memory as if by malloc(), the application
should release such memory when it is no longer required by a call to
free(). For strdup() and strndup(), this is the return value.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSOfree(), wcsdup()
The Base Definitions volume of POSIX.1‐2008, <string.h>
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri‐
cal and Electronics Engineers, Inc and The Open Group. (This is
POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) In the
event of any discrepancy between this version and the original IEEE and
The Open Group Standard, the original IEEE and The Open Group Standard
is the referee document. The original Standard can be obtained online
at http://www.unix.org/online.html .
Any typographical or formatting errors that appear in this page are
most likely to have been introduced during the conversion of the source
files to man page format. To report such errors, see https://www.ker‐
nel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group 2013 STRDUP(3P)
