fstat.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 FSTAT II 8/5/73
.sh NAME
fstat  \*-  get status of open file
.s3
.sh SYNOPSIS
(fstat = 28.)
.br
(file descriptor in r0)
.ft B
.br
sys fstat; buf
.s3
fstat(fildes, buf)
.br
struct inode *buf;
.ft R
.sh DESCRIPTION
This
call is identical to
.it stat,
except that it operates
on open files instead of files given by name.
It is most often used to get the status
of the standard input and output files, whose names
are unknown.
.sh "SEE ALSO"
stat (II)
.sh DIAGNOSTICS
The error bit
(c-bit) is set if the file descriptor is unknown;
from C, a \*-1 return indicates an error, 0 indicates success.