strdup(3) — Linux manual page

NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | ATTRIBUTES | STANDARDS | HISTORY | SEE ALSO

strdup(3)               Library Functions Manual               strdup(3)

NAME         top

       strdup, strndup, strdupa, strndupa - duplicate a string

LIBRARY         top

       Standard C library (libc, -lc)

SYNOPSIS         top

       #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         top

       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         top

       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         top

       ENOMEM Insufficient memory available to allocate duplicate
              string.

ATTRIBUTES         top

       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         top

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

       strdupa()
       strndupa()
              GNU.

HISTORY         top

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

       strndup()
              POSIX.1-2008.

       strdupa()
       strndupa()
              GNU.

SEE ALSO         top

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

Linux man-pages (unreleased)     (date)                        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)