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():
           _XOPEN_SOURCE >= 500
               || /* Since glibc 2.12: */ _POSIX_C_SOURCE >= 200809L
               || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
       strndup():
           Since glibc 2.10:
               _POSIX_C_SOURCE >= 200809L
           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 ('\0') 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.

ATTRIBUTES
       For an explanation of the terms used in this section, see attributes(7).

       -Œ---------------------------------¬----------------¬----------
       -‚Interface                       -‚ Attribute     -‚ Value   -‚
       "---------------------------------¼----------------¼----------¤
       -‚strdup(), strndup(), strdupa(), -‚ Thread safety -‚ MT-Safe -‚
       -‚strndupa()                      -‚               -‚         -‚
       ----------------------------------´----------------´---------"

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 4.15 of the Linux man-pages project.  A  description  of  the
       project,  information  about  reporting  bugs, and the latest version of this page, can be
       found at https://www.kernel.org/doc/man-pages/.

GNU                                         2017-09-15                                  STRDUP(3)