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39 lines
695 B
Groff
39 lines
695 B
Groff
.TH DUP 3
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.SH NAME
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dup \- duplicate an open file descriptor
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.SH SYNOPSIS
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.B #include <u.h>
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.br
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.B #include <libc.h>
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.PP
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.B
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int dup(int oldfd, int newfd)
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.SH DESCRIPTION
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Given a file descriptor,
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.IR oldfd ,
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referring to an open file,
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.I dup
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returns a new file descriptor referring to the same file.
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.PP
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If
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.I newfd
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is \-1 the system chooses the lowest available file descriptor.
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Otherwise,
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.I dup
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will use
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.I newfd
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for the new file descriptor
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(closing any old file associated with
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.IR newfd ).
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.SH SOURCE
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.B \*9/src/lib9/dup.c
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.SH DIAGNOSTICS
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Sets
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.IR errstr .
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.SH BUGS
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To avoid name conflicts with the underlying system,
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.I dup
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is a preprocessor macro defined as
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.IR p9dup ;
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see
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.MR intro (3) .
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