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STRDUP

Section: Linux Programmer's Manual (3)
Updated: 2010-09-15
Index Return to Main Contents
 

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():

Since glibc 2.12:
_SVID_SOURCE || _BSD_SOURCE || _XOPEN_SOURCE >= 500 || _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED || _POSIX_C_SOURCE >= 200809L
Before glibc 2.12:
_SVID_SOURCE || _BSD_SOURCE || _XOPEN_SOURCE >= 500 || _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED

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 only copies at most n characters. If s is longer than n, only n characters 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 only available when using the GNU GCC suite, and suffer from the same limitations described in alloca(3).  

RETURN VALUE

The strdup() function returns a pointer to the duplicated string, or NULL if insufficient memory was available.  

ERRORS

ENOMEM
Insufficient memory available to allocate duplicate string.
 

CONFORMING TO

strdup() conforms to SVr4, 4.3BSD, POSIX.1-2001. strndup(), 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 3.27 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/.


 

Index

NAME
SYNOPSIS
DESCRIPTION
RETURN VALUE
ERRORS
CONFORMING TO
SEE ALSO
COLOPHON

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