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
strndup(), 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), wcsdup(3)

COLOPHON¶

This page is part of release 3.22 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/.