xref: /freebsd/lib/libc/gen/setmode.3 (revision 6ae1554a5d9b318f8ad53ccc39fa5a961403da73)
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28.\"     @(#)setmode.3	8.2 (Berkeley) 4/28/95
29.\" $FreeBSD$
30.\"
31.Dd February 22, 2015
32.Dt SETMODE 3
33.Os
34.Sh NAME
35.Nm getmode ,
36.Nm setmode
37.Nd modify mode bits
38.Sh LIBRARY
39.Lb libc
40.Sh SYNOPSIS
41.In unistd.h
42.Ft mode_t
43.Fn getmode "const void *set" "mode_t mode"
44.Ft void *
45.Fn setmode "const char *mode_str"
46.Sh DESCRIPTION
47The
48.Fn getmode
49function
50returns a copy of the file permission bits
51.Fa mode
52as altered by the values pointed to by
53.Fa set .
54While only the mode bits are altered, other parts of the file mode
55may be examined.
56.Pp
57The
58.Fn setmode
59function
60takes an absolute (octal) or symbolic value, as described in
61.Xr chmod 1 ,
62as an argument
63and returns a pointer to mode values to be supplied to
64.Fn getmode .
65Because some of the symbolic values are relative to the file
66creation mask,
67.Fn setmode
68may call
69.Xr umask 2 .
70If this occurs, the file creation mask will be restored before
71.Fn setmode
72returns.
73If the calling program changes the value of its file creation mask
74after calling
75.Fn setmode ,
76.Fn setmode
77must be called again if
78.Fn getmode
79is to modify future file modes correctly.
80.Pp
81If the mode passed to
82.Fn setmode
83is invalid or if memory cannot be allocated for the return value,
84.Fn setmode
85returns
86.Dv NULL .
87.Pp
88The value returned from
89.Fn setmode
90is obtained from
91.Fn malloc
92and should be returned to the system with
93.Fn free
94when the program is done with it, generally after a call to
95.Fn getmode .
96.Sh ERRORS
97The
98.Fn setmode
99function
100may fail and set errno for any of the errors specified for the library
101routine
102.Xr malloc 3
103or
104.Xr strtol 3 .
105In addition,
106.Fn setmode
107will fail and set
108.Va errno
109to:
110.Bl -tag -width Er
111.It Bq Er EINVAL
112The
113.Fa mode
114argument does not represent a valid mode.
115.El
116.Sh SEE ALSO
117.Xr chmod 1 ,
118.Xr stat 2 ,
119.Xr umask 2 ,
120.Xr malloc 3
121.Sh HISTORY
122The
123.Fn getmode
124and
125.Fn setmode
126functions first appeared in
127.Bx 4.4 .
128