xref: /freebsd/lib/libc/gen/setmode.3 (revision f0adf7f5cdd241db2f2c817683191a6ef64a4e95)
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32.\"     @(#)setmode.3	8.2 (Berkeley) 4/28/95
33.\" $FreeBSD$
34.\"
35.Dd April 28, 1995
36.Dt SETMODE 3
37.Os
38.Sh NAME
39.Nm getmode ,
40.Nm setmode
41.Nd modify mode bits
42.Sh LIBRARY
43.Lb libc
44.Sh SYNOPSIS
45.In unistd.h
46.Ft mode_t
47.Fn getmode "const void *set" "mode_t mode"
48.Ft void *
49.Fn setmode "const char *mode_str"
50.Sh DESCRIPTION
51The
52.Fn getmode
53function
54returns a copy of the file permission bits
55.Fa mode
56as altered by the values pointed to by
57.Fa set .
58While only the mode bits are altered, other parts of the file mode
59may be examined.
60.Pp
61The
62.Fn setmode
63function
64takes an absolute (octal) or symbolic value, as described in
65.Xr chmod 1 ,
66as an argument
67and returns a pointer to mode values to be supplied to
68.Fn getmode .
69Because some of the symbolic values are relative to the file
70creation mask,
71.Fn setmode
72may call
73.Xr umask 2 .
74If this occurs, the file creation mask will be restored before
75.Fn setmode
76returns.
77If the calling program changes the value of its file creation mask
78after calling
79.Fn setmode ,
80.Fn setmode
81must be called again if
82.Fn getmode
83is to modify future file modes correctly.
84.Pp
85If the mode passed to
86.Fn setmode
87is invalid or if memory cannot be allocated for the return value,
88.Fn setmode
89returns
90.Dv NULL .
91.Pp
92The value returned from
93.Fn setmode
94is obtained from
95.Fn malloc
96and should be returned to the system with
97.Fn free
98when the program is done with it, generally after a call to
99.Fn getmode .
100.Sh ERRORS
101The
102.Fn setmode
103function
104may fail and set errno for any of the errors specified for the library
105routine
106.Xr malloc 3 .
107.Sh SEE ALSO
108.Xr chmod 1 ,
109.Xr stat 2 ,
110.Xr umask 2 ,
111.Xr malloc 3
112.Sh HISTORY
113The
114.Fn getmode
115and
116.Fn setmode
117functions first appeared in
118.Bx 4.4 .
119