xref: /freebsd/lib/libsys/closefrom.2 (revision ae07a5805b1906f29e786f415d67bef334557bd3)
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26.Dd May 17, 2025
27.Dt CLOSEFROM 2
28.Os
29.Sh NAME
30.Nm closefrom ,
31.Nm close_range
32.Nd delete open file descriptors
33.Sh LIBRARY
34.Lb libc
35.Sh SYNOPSIS
36.In unistd.h
37.Ft void
38.Fn closefrom "int lowfd"
39.Ft int
40.Fn close_range "u_int lowfd" "u_int highfd" "int flags"
41.Sh DESCRIPTION
42The
43.Fn closefrom
44system call deletes all open file descriptors greater than or equal to
45.Fa lowfd
46from the per-process object reference table.
47Any errors encountered while closing file descriptors are ignored.
48.Pp
49The
50.Fn close_range
51system call deletes all open file descriptors between
52.Fa lowfd
53and
54.Fa highfd
55inclusive, clamped to the range of open file descriptors.
56Any errors encountered while closing file descriptors are ignored.
57Supported
58.Fa flags :
59.Bl -tag -width ".Dv CLOSE_RANGE_CLOEXEC"
60.It Dv CLOSE_RANGE_CLOEXEC
61Set the close-on-exec flag on descriptors in the range instead of closing them.
62.It Dv CLOSE_RANGE_CLOFORK
63Set the close-on-fork flag on descriptors in the range instead of closing them.
64.El
65.Sh RETURN VALUES
66Upon successful completion,
67.Fn close_range
68returns a value
69of 0.
70Otherwise, a value of -1 is returned and the global variable
71.Va errno
72is set to indicate the error.
73.Sh ERRORS
74The
75.Fn close_range
76system call
77will fail if:
78.Bl -tag -width Er
79.It Bq Er EINVAL
80The
81.Fa highfd
82argument is lower than the
83.Fa lowfd
84argument.
85.It Bq Er EINVAL
86An invalid flag was set.
87.El
88.Sh SEE ALSO
89.Xr close 2
90.Sh HISTORY
91The
92.Fn closefrom
93function first appeared in
94.Fx 8.0 .
95.Pp
96The
97.Dv CLOSE_RANGE_CLOFORK
98flag appeared in
99.Fx 15.0 .
100