fseek.3f

来自「<B>Digital的Unix操作系统VAX 4.2源码</B>」· 3F 代码 · 共 54 行

.\" SCCSID: @(#)fseek.3f	8.1	9/11/90
.TH fseek 3f VAX "" Unsupported
.SH Name
fseek, ftell \- reposition a file on a logical unit
.SH Syntax
.B integer function fseek (lunit, offset, from)
.br
.B integer offset, from
.sp 1
.B integer function ftell (lunit)
.SH Description
.NXR "fseek subroutine (FORTRAN)"
.NXR "ftell subroutine (FORTRAN)"
.NXR "file" "repositioning on logical unit"
The
.I lunit
argument must refer to an open logical unit.
The
.I offset
argument 
is an offset in bytes relative to the position specified by
.I from.
Valid values for
.I from
are:
.sp 1
.in +5
0 meaning 'beginning of the file'
.br
1 meaning 'the current position'
.br
2 meaning 'the end of the file'
.in \-5
.PP
The value returned by
.PN fseek
will be 0 if successful, a system error code otherwise.
See 
.MS perror 3f .
.PP
The
.PN ftell
function returns the current position of the file 
associated with the specified logical unit. The value 
is an offset, in bytes, from the beginning of the file.
If the value returned is negative, it indicates an error 
and will be the negation of the system error code. See 
.MS perror 3f .
.SH Files
.ie \nM /usr/ucb/lib/libU77.a
.el /usr/lib/libU77.a
.SH See Also
perror(3f), fseek(3s)