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).

   
   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

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