strdupa(3)

strdupa3

Save a copy of a string

Part of strdup(3).

Usage

#include <string.h>

char *

strdup(const char *str);

char *

strdupa(const char *str);

char *

strndup(const char *str, size_t len);

char *

strndupa(const char *str, size_t len);

Library

Standard C Library (libc, -lc)

Overview

The strdup() function allocates sufficient memory for a copy of the string str, does the copy, and returns a pointer to it. The memory is allocated with malloc(3) and should be released with free(3) when no longer needed.

The strndup() function copies at most len characters from the string str always NUL terminating the copied string.

The strdupa() function is identical to strdup() but allocates the memory with alloca(3). Similarly, the strndupa() function is identical to strndup(), but allocates the memory with alloca(3).

Return values

If insufficient memory is available, NULL is returned and errno is set to ENOMEM. Otherwise, the strdup() family of functions return a pointer to the copied string.

Releases

4 releases since FreeBSD 14.4-RELEASE; the text changed 1 time.

  1. 14.4–14.5
  2. 15.1–16.0

Standards

The strdup() function is specified by IEEE Std 1003.1-2001 (“POSIX.1”). The strndup() function is specified by IEEE Std 1003.1-2008 (“POSIX.1”). The strdupa() and strndupa() functions are extensions, taken from glibc.

History

The strdup() function first appeared in 4.3BSD-Reno. The strndup() function was added in FreeBSD 7.2. The strdupa() and strndupa() functions were added in FreeBSD 15.1.

From base 16.0-CURRENT-20261027-61c70dc16a79 in FreeBSD 16.0-CURRENT (2026-10-27). Parsed by carta from the page's mdoc source.