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 ('\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).

       ┌────────────────────────────────┬───────────────┬─────────┐
       │Interface                       │ Attribute     │ Value   │
       ├────────────────────────────────┼───────────────┼─────────┤
       │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 4.04 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 http://www.kernel.org/doc/man-pages/.