HP Pascal/iX Reference Manual (31502-90022)

10- 19
reset
Usage
reset (f)
reset (f, s)
reset (f, s, t)
Parameters
f A file variable that may not be omitted.
s The name of a physical file that the system associates with f . s
may be a string or PAC expression.
t An options string that may be a string or PAC expression whose value
is implementation dependent.
Description
The procedure reset (f) opens the file f in the input state and places the
current position at the first component. The contents of f , if any, are
undisturbed. The file f may then be read sequentially.
If f is not empty, eof (f) is false, and a subsequent reference to the
buffer variable f^ actually loads the buffer with the first component.
The components of f may now be read in sequence. If f is empty, however,
eof (f) is true and f^ is undefined, then subsequent calls to read are
errors.
If f is already open at the time reset is called, the system
automatically closes and then reopens it, retaining the contents of the
file. If the parameter s is specified, the system closes any physical
file previously associated with f .
When f does not appear as a program parameter and s is not specified, the
system maintains any previous association of a physical file with f . For
more information on opening files, see the HP Pascal/iX Programmer's
Guide or the HP Pascal/HP-UX Programmer's Guide , depending on your
implementation.
Example
reset(file_var)
reset(file_var,file_name)
reset(file_var,file_name,opt_str)
Illustration
Suppose examp_file is a closed file of char with three components. To
read sequentially from examp_file, we call reset: