3 cfa37a7b 2004-04-10 devnull dup \- duplicate an open file descriptor
4 cfa37a7b 2004-04-10 devnull .SH SYNOPSIS
5 cfa37a7b 2004-04-10 devnull .B #include <u.h>
7 cfa37a7b 2004-04-10 devnull .B #include <libc.h>
10 cfa37a7b 2004-04-10 devnull int dup(int oldfd, int newfd)
11 cfa37a7b 2004-04-10 devnull .SH DESCRIPTION
12 cfa37a7b 2004-04-10 devnull Given a file descriptor,
13 cfa37a7b 2004-04-10 devnull .IR oldfd ,
14 cfa37a7b 2004-04-10 devnull referring to an open file,
16 cfa37a7b 2004-04-10 devnull returns a new file descriptor referring to the same file.
20 cfa37a7b 2004-04-10 devnull is \-1 the system chooses the lowest available file descriptor.
21 cfa37a7b 2004-04-10 devnull Otherwise,
25 cfa37a7b 2004-04-10 devnull for the new file descriptor
26 cfa37a7b 2004-04-10 devnull (closing any old file associated with
27 cfa37a7b 2004-04-10 devnull .IR newfd ).
28 cfa37a7b 2004-04-10 devnull File descriptors are allocated dynamically,
29 cfa37a7b 2004-04-10 devnull so to prevent unwarranted growth of the file descriptor table,
31 cfa37a7b 2004-04-10 devnull requires that
33 cfa37a7b 2004-04-10 devnull be no greater than 20 more than the highest file descriptor ever used by
34 cfa37a7b 2004-04-10 devnull the program.
35 cfa37a7b 2004-04-10 devnull .SH SOURCE
36 b5fdffee 2004-04-19 devnull .B /usr/local/plan9/src/libc/9syscall
37 cfa37a7b 2004-04-10 devnull .SH SEE ALSO
38 bf8a59fa 2004-04-11 devnull .IR intro (3),
39 cfa37a7b 2004-04-10 devnull .IR dup (3)
40 cfa37a7b 2004-04-10 devnull .SH DIAGNOSTICS
42 cfa37a7b 2004-04-10 devnull .IR errstr .