strdup(3) — Linux manual page

strdup(3)               Library Functions Manual               strdup(3)

NAME

       strdup, strndup, strdupa, strndupa - duplicate a string

LIBRARY

       Standard C library (libc, -lc)

SYNOPSIS

       #include <string.h>

       char *strdup(const char *s);

       char *strndup(const char s[.n], size_t n);
       char *strdupa(const char *s);
       char *strndupa(const char s[.n], 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.

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

STANDARDS

       strdup()
       strndup()
              POSIX.1-2008.

       strdupa()
       strndupa()
              GNU.

HISTORY

       strdup()
              SVr4, 4.3BSD-Reno, POSIX.1-2001.

       strndup()
              POSIX.1-2008.

       strdupa()
       strndupa()
              GNU.

SEE ALSO

       alloca(3), calloc(3), free(3), malloc(3), realloc(3), string(3),
       wcsdup(3)

COLOPHON

       This page is part of the man-pages (Linux kernel and C library
       user-space interface documentation) project.  Information about
       the project can be found at 
       ⟨https://www.kernel.org/doc/man-pages/⟩.  If you have a bug report
       for this manual page, see
       ⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩.
       This page was obtained from the tarball man-pages-6.9.1.tar.gz
       fetched from
       ⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on
       2024-06-26.  If you discover any rendering problems in this HTML
       version of the page, or you believe there is a better or more up-
       to-date source for the page, or you have corrections or
       improvements to the information in this COLOPHON (which is not
       part of the original manual page), send a mail to
       man-pages@man7.org

Linux man-pages 6.9.1          2024-06-15                      strdup(3)

Pages that refer to this page: alloca(3), ldap_memory(3), pmdadaemon(3), pmdafetch(3), pmfault(3), pmtraversepmns(3), strcpy(3), string(3), wcsdup(3), string_copying(7)

---