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| author | rsc <devnull@localhost> | 2004-04-10 18:53:55 +0000 |
|---|---|---|
| committer | rsc <devnull@localhost> | 2004-04-10 18:53:55 +0000 |
| commit | cfa37a7b1131abbab2e7d339b451f5f0e3198cc8 (patch) | |
| tree | a7fe52416e9d27efe2af2d54910112674c0fd7c6 /man/man3/dup.3 | |
| parent | 08df2a433e69c94f9db002c83380cb2b693fee60 (diff) | |
| download | plan9port-cfa37a7b1131abbab2e7d339b451f5f0e3198cc8.tar.gz plan9port-cfa37a7b1131abbab2e7d339b451f5f0e3198cc8.tar.bz2 plan9port-cfa37a7b1131abbab2e7d339b451f5f0e3198cc8.zip | |
Lots of man pages.
Diffstat (limited to 'man/man3/dup.3')
| -rw-r--r-- | man/man3/dup.3 | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/man/man3/dup.3 b/man/man3/dup.3 new file mode 100644 index 00000000..83f98fe1 --- /dev/null +++ b/man/man3/dup.3 @@ -0,0 +1,42 @@ +.TH DUP 3 +.SH NAME +dup \- duplicate an open file descriptor +.SH SYNOPSIS +.B #include <u.h> +.br +.B #include <libc.h> +.PP +.B +int dup(int oldfd, int newfd) +.SH DESCRIPTION +Given a file descriptor, +.IR oldfd , +referring to an open file, +.I dup +returns a new file descriptor referring to the same file. +.PP +If +.I newfd +is \-1 the system chooses the lowest available file descriptor. +Otherwise, +.I dup +will use +.I newfd +for the new file descriptor +(closing any old file associated with +.IR newfd ). +File descriptors are allocated dynamically, +so to prevent unwarranted growth of the file descriptor table, +.I dup +requires that +.I newfd +be no greater than 20 more than the highest file descriptor ever used by +the program. +.SH SOURCE +.B /sys/src/libc/9syscall +.SH SEE ALSO +.IR intro (2), +.IR dup (3) +.SH DIAGNOSTICS +Sets +.IR errstr . |