xref: /freebsd/lib/libc/gen/setmode.3 (revision 380a989b3223d455375b4fae70fd0b9bdd43bafb)
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32.\"     @(#)setmode.3	8.2 (Berkeley) 4/28/95
33.\"
34.Dd April 28, 1995
35.Dt SETMODE 3
36.Os
37.Sh NAME
38.Nm getmode ,
39.Nm setmode
40.Nd modify mode bits
41.Sh SYNOPSIS
42.Fd #include <unistd.h>
43.Ft mode_t
44.Fn getmode "const void *set" "mode_t mode"
45.Ft void *
46.Fn setmode "const char *mode_str"
47.Sh DESCRIPTION
48The
49.Fn getmode
50function
51returns a copy of the file permission bits
52.Fa mode
53as altered by the values pointed to by
54.Fa set .
55While only the mode bits are altered, other parts of the file mode
56may be examined.
57.Pp
58The
59.Fn setmode
60function
61takes an absolute (octal) or symbolic value, as described in
62.Xr chmod 1 ,
63as an argument
64and returns a pointer to mode values to be supplied to
65.Fn getmode .
66Because some of the symbolic values are relative to the file
67creation mask,
68.Fn setmode
69may call
70.Xr umask 2 .
71If this occurs, the file creation mask will be restored before
72.Fn setmode
73returns.
74If the calling program changes the value of its file creation mask
75after calling
76.Fn setmode ,
77.Fn setmode
78must be called again if
79.Fn getmode
80is to modify future file modes correctly.
81.Pp
82If the mode passed to
83.Fn setmode
84is invalid or if memory cannot be allocated for the return value,
85.Fn setmode
86returns
87.Dv NULL .
88.Pp
89The value returned from
90.Fn setmode
91is obtained from
92.Fn malloc
93and should be returned to the system with
94.Fn free
95when the program is done with it, generally after a call to
96.Fn getmode .
97.Sh ERRORS
98The
99.Fn setmode
100function
101may fail and set errno for any of the errors specified for the library
102routine
103.Xr malloc 3 .
104.Sh SEE ALSO
105.Xr chmod 1 ,
106.Xr stat 2 ,
107.Xr umask 2 ,
108.Xr malloc 3
109.Sh HISTORY
110The
111.Fn getmode
112and
113.Fn setmode
114functions first appeared in
115.Bx 4.4 .
116