Re: binding to non-existent file

On 31/03/16 06:20, Paul Isaacs wrote:
> Hello,
> 
> I am following the example from page 94 of the GNU pascal manual.
> 
> bind( f,b);
> b := binding( f );
> 
> b.bound appears to be true even though the file does not exist although
> the example indicates otherwise.
> 
> I have duplicated the example - it finds a non-existent file.
> 
> Is the example wrong ( the same example is in the standard )?
> 
> Regards,
> 
> Paul Isaacs
> 
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I suspect that for b.bound to be true just needs a valid file name (like
the Borland Pascal assign). b.Existing should be used to check for file
existance.

The full example (I've not tried it) from page 110 of the manual is here

----------------------------
procedure BindFile (var f: Text);
var
	b: BindingType;
begin
	Unbind (f);
	b := Binding (f);
	repeat
		Write (’Enter a file name: ’);
		ReadLn (b.Name);
		Bind (f, b);
		b := Binding (f);
		if not b.Bound then
			WriteLn (’File not bound -- try again.’)
	until b.Bound
end;

begin
	BindFile (f);
	{ Now the file f is bound to an external file. We can use the
	implementation defined fields of BindingType to check if the
	file exists and is readable, writable or executable. }
	b := Binding (f);
	Write (’The file ’);
	if b.Existing then     	{ <<-- **************************** }
		WriteLn (’exists.’)
	else
		WriteLn (’does not exist.’);
	Write (’It is ’);
	if not b.Readable then Write (’not ’);
		Write (’readable, ’);
	if not b.Writable then Write (’not ’);
		Write (’writable and ’);
	if not b.Executable then Write (’not ’);
		WriteLn (’executable.’)
end.
----------------------------


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