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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 <= 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)

GNU                                                                            2021-03-22                                                                      STRDUP(3)