strndup(3)

1strdup(3)                  Library Functions Manual                  strdup(3)
2
3
4

NAME

6       strdup, strndup, strdupa, strndupa - duplicate a string
7

LIBRARY

9       Standard C library (libc, -lc)
10

SYNOPSIS

12       #include <string.h>
13
14       char *strdup(const char *s);
15
16       char *strndup(const char s[.n], size_t n);
17       char *strdupa(const char *s);
18       char *strndupa(const char s[.n], size_t n);
19
20   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
21
22       strdup():
23           _XOPEN_SOURCE >= 500
24               || /* Since glibc 2.12: */ _POSIX_C_SOURCE >= 200809L
25               || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
26
27       strndup():
28           Since glibc 2.10:
29               _POSIX_C_SOURCE >= 200809L
30           Before glibc 2.10:
31               _GNU_SOURCE
32
33       strdupa(), strndupa():
34           _GNU_SOURCE
35

DESCRIPTION

37       The  strdup() function returns a pointer to a new string which is a du‐
38       plicate of the string s.  Memory for the new string  is  obtained  with
39       malloc(3), and can be freed with free(3).
40
41       The strndup() function is similar, but copies at most n bytes.  If s is
42       longer than n, only n bytes are copied, and  a  terminating  null  byte
43       ('\0') is added.
44
45       strdupa() and strndupa() are similar, but use alloca(3) to allocate the
46       buffer.
47

RETURN VALUE

49       On success, the strdup() function returns a pointer to  the  duplicated
50       string.  It returns NULL if insufficient memory was available, with er‐
51       rno set to indicate the error.
52

ERRORS

54       ENOMEM Insufficient memory available to allocate duplicate string.
55

ATTRIBUTES

57       For an  explanation  of  the  terms  used  in  this  section,  see  at‐
58       tributes(7).
59
60       ┌────────────────────────────────────────────┬───────────────┬─────────┐
61       │Interface                                   │ Attribute     │ Value   │
62       ├────────────────────────────────────────────┼───────────────┼─────────┤
63       │strdup(), strndup(), strdupa(), strndupa()  │ Thread safety │ MT-Safe │
64       └────────────────────────────────────────────┴───────────────┴─────────┘
65

STANDARDS

67       strdup()
68       strndup()
69              POSIX.1-2008.
70
71       strdupa()
72       strndupa()
73              GNU.
74

HISTORY

76       strdup()
77              SVr4, 4.3BSD-Reno, POSIX.1-2001.
78
79       strndup()
80              POSIX.1-2008.
81
82       strdupa()
83       strndupa()
84              GNU.
85