xref: /freebsd/lib/libc/gen/setmode.3 (revision 4cf49a43559ed9fdad601bdcccd2c55963008675)
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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 SYNOPSIS
43.Fd #include <unistd.h>
44.Ft mode_t
45.Fn getmode "const void *set" "mode_t mode"
46.Ft void *
47.Fn setmode "const char *mode_str"
48.Sh DESCRIPTION
49The
50.Fn getmode
51function
52returns a copy of the file permission bits
53.Fa mode
54as altered by the values pointed to by
55.Fa set .
56While only the mode bits are altered, other parts of the file mode
57may be examined.
58.Pp
59The
60.Fn setmode
61function
62takes an absolute (octal) or symbolic value, as described in
63.Xr chmod 1 ,
64as an argument
65and returns a pointer to mode values to be supplied to
66.Fn getmode .
67Because some of the symbolic values are relative to the file
68creation mask,
69.Fn setmode
70may call
71.Xr umask 2 .
72If this occurs, the file creation mask will be restored before
73.Fn setmode
74returns.
75If the calling program changes the value of its file creation mask
76after calling
77.Fn setmode ,
78.Fn setmode
79must be called again if
80.Fn getmode
81is to modify future file modes correctly.
82.Pp
83If the mode passed to
84.Fn setmode
85is invalid or if memory cannot be allocated for the return value,
86.Fn setmode
87returns
88.Dv NULL .
89.Pp
90The value returned from
91.Fn setmode
92is obtained from
93.Fn malloc
94and should be returned to the system with
95.Fn free
96when the program is done with it, generally after a call to
97.Fn getmode .
98.Sh ERRORS
99The
100.Fn setmode
101function
102may fail and set errno for any of the errors specified for the library
103routine
104.Xr malloc 3 .
105.Sh SEE ALSO
106.Xr chmod 1 ,
107.Xr stat 2 ,
108.Xr umask 2 ,
109.Xr malloc 3
110.Sh HISTORY
111The
112.Fn getmode
113and
114.Fn setmode
115functions first appeared in
116.Bx 4.4 .
117