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 <= 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 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(), strndupa()                     │ Thread safety │ MT-Safe │
       └───────────────────────────────────────────────────────────────┴───────────────┴─────────┘

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 5.13 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/.