tostring is working properly ?

[Paolo]

Hello,

incidentally I see that the code below compile with double variabile but not with real variabile, is this bheaviour the expected one ? (really I do not make use of real type, but I noted this), doesn't real is an alias of double ?

Code: Pascal  [Select][+][-]

1. procedure TForm1.Button5Click(Sender: TObject);
2. var
3.   a : real;
4.   b : double;
5.   c : string;
6. begin
7.   c:=a.tostring;  <--- it does not compile
8.   c:=b.tostring;  <--- it compiles
9. end;
10.  

laz 2.2.2, fpc 3.2.2 win10

[mirce.vladimirov]

I dont realy know about this, I am using :

Code: Pascal  [Select][+][-]

1. c:=floattostr(a) ;
2. c:=floattostr(b);
3. c:=inttostr(some_integer_variable);
4.  

There are also oposite strtoint() and strtofloat()

[PascalDragon]

incidentally I see that the code below compile with double variabile but not with real variabile, is this bheaviour the expected one ? (really I do not make use of real type, but I noted this), doesn't real is an alias of double ?

Real is a unique alias of Double (type Real = type Double vs. type Real = Double) and thus type helpers for Double are not in scope for Real variables. So yes, this is expected behaviour.

[Paolo]

thanks for the explaination. (It is the expected behaviour according to type definition, but is it the desired behaviour ? )

We can say that "tostring" is less portable than "/floattostr/flrotstrF/etc.." family. Having code with double and a lot of "tostring" if the type is changed to real casues a lot of compiler errors.

(But again it is not a real isssue for me, since I am using only double type since long time ago...)

[dsiders]

We can say that "tostring" is less portable than "/floattostr/flrotstrF/etc.." family. Having code with double and a lot of "tostring" if the type is changed to real casues a lot of compiler errors.

But Real.ToString is exactly as portable as the StrtoReal and RealToString routines. Because they don't exist either.

[Paolo]

but this works

Code: Pascal  [Select][+][-]

1. procedure TForm1.Button5Click(Sender: TObject);
2. var
3.   a : real;
4.   b : double;
5.   c : string;
6. begin
7.   c:=FloatToStr(a); //<--- this compile
8.   c:=b.tostring;
9. end;
10.  

[PascalDragon]

thanks for the explaination. (It is the expected behaviour according to type definition, but is it the desired behaviour ? )

Well, feel free to open a bug report to add a type helper for Real as well.

We can say that "tostring" is less portable than "/floattostr/flrotstrF/etc.." family. Having code with double and a lot of "tostring" if the type is changed to real casues a lot of compiler errors.

Real is simply a legacy type from TP times and considering that Delphi tends to ignore legacy types and that type helpers are a concept introduced by Delphi there was simply no type helper added for Real.

but this works

Code: Pascal  [Select][+][-]

1. procedure TForm1.Button5Click(Sender: TObject);
2. var
3.   a : real;
4.   b : double;
5.   c : string;
6. begin
7.   c:=FloatToStr(a); //<--- this compile
8.   c:=b.tostring;
9. end;
10.  

Because the compiler can convert Real to Double, but for declaring overloads and for type helpers an exact type match is necessary.