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[dragonfly.git] / lib / libc / gen / setmode.3
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32.\" @(#)setmode.3 8.2 (Berkeley) 4/28/95
33.\" $FreeBSD: src/lib/libc/gen/setmode.3,v 1.8.2.3 2001/12/14 18:33:51 ru Exp $
1de703da 34.\" $DragonFly: src/lib/libc/gen/setmode.3,v 1.2 2003/06/17 04:26:42 dillon Exp $
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35.\"
36.Dd April 28, 1995
37.Dt SETMODE 3
38.Os
39.Sh NAME
40.Nm getmode ,
41.Nm setmode
42.Nd modify mode bits
43.Sh LIBRARY
44.Lb libc
45.Sh SYNOPSIS
46.In unistd.h
47.Ft mode_t
48.Fn getmode "const void *set" "mode_t mode"
49.Ft void *
50.Fn setmode "const char *mode_str"
51.Sh DESCRIPTION
52The
53.Fn getmode
54function
55returns a copy of the file permission bits
56.Fa mode
57as altered by the values pointed to by
58.Fa set .
59While only the mode bits are altered, other parts of the file mode
60may be examined.
61.Pp
62The
63.Fn setmode
64function
65takes an absolute (octal) or symbolic value, as described in
66.Xr chmod 1 ,
67as an argument
68and returns a pointer to mode values to be supplied to
69.Fn getmode .
70Because some of the symbolic values are relative to the file
71creation mask,
72.Fn setmode
73may call
74.Xr umask 2 .
75If this occurs, the file creation mask will be restored before
76.Fn setmode
77returns.
78If the calling program changes the value of its file creation mask
79after calling
80.Fn setmode ,
81.Fn setmode
82must be called again if
83.Fn getmode
84is to modify future file modes correctly.
85.Pp
86If the mode passed to
87.Fn setmode
88is invalid or if memory cannot be allocated for the return value,
89.Fn setmode
90returns
91.Dv NULL .
92.Pp
93The value returned from
94.Fn setmode
95is obtained from
96.Fn malloc
97and should be returned to the system with
98.Fn free
99when the program is done with it, generally after a call to
100.Fn getmode .
101.Sh ERRORS
102The
103.Fn setmode
104function
105may fail and set errno for any of the errors specified for the library
106routine
107.Xr malloc 3 .
108.Sh SEE ALSO
109.Xr chmod 1 ,
110.Xr stat 2 ,
111.Xr umask 2 ,
112.Xr malloc 3
113.Sh HISTORY
114The
115.Fn getmode
116and
117.Fn setmode
118functions first appeared in
119.Bx 4.4 .