xref: /freebsd/lib/libc/string/strdup.3 (revision dcc4d2939f789a6d1f272ffeab2068ba2b7525ea)
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28.\"     @(#)strdup.3	8.1 (Berkeley) 6/9/93
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30.Dd May 5, 2020
31.Dt STRDUP 3
32.Os
33.Sh NAME
34.Nm strdup ,
35.Nm strndup
36.Nd save a copy of a string
37.Sh LIBRARY
38.Lb libc
39.Sh SYNOPSIS
40.In string.h
41.Ft char *
42.Fn strdup "const char *str"
43.Ft char *
44.Fn strndup "const char *str" "size_t len"
45.Sh DESCRIPTION
46The
47.Fn strdup
48function
49allocates sufficient memory for a copy
50of the string
51.Fa str ,
52does the copy, and returns a pointer to it.
53The memory is allocated with
54.Xr malloc 3
55and should be released with
56.Xr free 3
57when no longer needed.
58.Pp
59The
60.Fn strndup
61function copies at most
62.Fa len
63characters from the string
64.Fa str
65always
66.Dv NUL
67terminating the copied string.
68.Sh RETURN VALUES
69If insufficient memory is available, NULL is returned and
70.Va errno
71is set to
72.Er ENOMEM .
73Otherwise, the
74.Fn strdup
75family of functions return a pointer to the copied string.
76.Sh SEE ALSO
77.Xr free 3 ,
78.Xr malloc 3 ,
79.Xr wcsdup 3
80.Sh STANDARDS
81The
82.Fn strdup
83function is specified by
84.St -p1003.1-2001 .
85The
86.Fn strndup
87function is specified by
88.St -p1003.1-2008 .
89.Sh HISTORY
90The
91.Fn strdup
92function first appeared in
93.Bx 4.3 Reno .
94The
95.Fn strndup
96function was added in
97.Fx 7.2 .
98