'ReadStr' ?

[J-G]

Looking back at some projects I did some tme ago, I've found a call to 'ReadStr' which the complier hinted that it didn't recognise - and I couldn't find a function or procedure that had that name  -  but the project did compile. A little research and I found that it actually calls function TControl.GetText in [Control.inc].

Today I would use :

Code: Pascal  [Select][+][-]

1. Numb := StrToInt(Orig_Numb.Caption);

Whereas my old code has :

Code: Pascal  [Select][+][-]

1. ReadStr(Orig_Num.Caption,Numb);

This discrepancy has me wondering why I used the ReadStr?  when today I can't remember ever knowing that such a call existed.  It may have been suggested to me via a forum post but I can't find such.

My real question is "Is there any benefit (or Dis) to either method cited"?

[marcov]

read/writestr are read and writes to and from strings.  Some other Pascal dialects have them, and as it seemed useful, they were enabled in other modes too. I assume errorhandling is the same with {$I-}  and checking IORESULT.

Strtoint is the delphi way, and can throw exceptions, better use strtointdef or trystrtoint.

[J-G]

Thanks @Marcov,  as is fairly usual, my questions elicit more!!

At least I am better informed over ReadStr but yet again I'll need to do more research on strtointdef and trystrtoint   

[Thaddy]

we also have str/val for int to string to int conversions and purists would call only those Pascal.
These are intrinsics. ReadStr/WriteStr come from ISO pascal.

[J-G]

we also have str/val for int to string to int conversions and purists would call only those Pascal.
These are intrinsics. ReadStr/WriteStr come from ISO pascal.

I'll have to admit that I'd forgotten about Str / Val but (having looked again at how they 'work' ) feel that IntToStr/StrToInt are simpler options.

With Str(X,S) the S must be a variable whereas I generally wish to assign the value of a number to the 'Caption' of a TLabel (or suchlike). No doubt I could create a var which I thereafter assign to the 'Caption' but that is just counter-productive.

[PascalDragon]

read/writestr are read and writes to and from strings.  Some other Pascal dialects have them, and as it seemed useful, they were enabled in other modes too. I assume errorhandling is the same with {$I-}  and checking IORESULT.

Strtoint is the delphi way, and can throw exceptions, better use strtointdef or trystrtoint.

And in {$I+} it will just as well throw exceptions:

Code: Pascal  [Select][+][-]

1. program treadstr;
2.  
3. {$mode objfpc}{$H+}
4.  
5. uses
6.   SysUtils;
7.  
8. var
9.   s: String;
10.   l: LongInt;
11. begin
12.   try
13.     s := 'Foo';
14.     ReadStr(s, l);
15.     Writeln(l);
16.   except
17.     on e: Exception do
18.       Writeln(e.ClassName, ': ', e.Message);
19.   end;
20. end.

Output:

Code: [Select]

EInOutError: Invalid input