close.2

UNIX v6源代码 这几乎是最经典的unix版本 unix操作系统设计和莱昂氏unix源代码分析都是用的该版

.th CLOSE II 8/5/73
.sh NAME
close  \*-  close a file
.sh SYNOPSIS
(close = 6.)
.br
(file descriptor in r0)
.br
.ft B
sys close
.s3
close(fildes)
.s3
.ft R
.sh DESCRIPTION
Given
a file descriptor such as returned from an
.it open,
.it creat,
or
.it pipe
call,
.it close
closes the associated file.
A close of all files is automatic on
.it exit,
but since
processes are limited to 15 simultaneously open files,
.it close
is necessary for programs which deal with many files.
.sh "SEE ALSO"
creat (II), open (II), pipe (II)
.sh DIAGNOSTICS
The error bit
(c-bit) is set for an unknown file descriptor.
From C a \*-1 indicates an error, 0 indicates
success.