strdup(3p) [posix man page]

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 correspond-
       ing 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 success. 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 ALSO

       free(), 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 Technol-
       ogy  --	Portable  Operating  System  Interface (POSIX), The Open Group Base Specifications Issue 7, Copyright (C) 2013 by the Institute of
       Electrical 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 Stan-
       dard 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.kernel.org/doc/man-pages/reporting_bugs.html .

IEEE
/The Open Group						       2013								STRDUP(3P)

Check Out this Related Man Page

STRDUP(3)						     Linux Programmer's Manual							 STRDUP(3)

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():
	   _SVID_SOURCE || _BSD_SOURCE || _XOPEN_SOURCE >= 500 || _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED
	   || /* Since glibc 2.12: */ _POSIX_C_SOURCE >= 200809L
       strndup():
	   Since glibc 2.10:
	       POSIX_C_SOURCE >= 200809L || _XOPEN_SOURCE >= 700
	   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
       ('') 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.

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 3.53 of the Linux man-pages project.  A description of the project, and information about reporting bugs, can
       be found at http://www.kernel.org/doc/man-pages/.

GNU
								    2013-04-19								 STRDUP(3)

Linux and UNIX Man Pages

strdup(3p) [posix man page]

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