Converting a string to Cardinal / UInt32

Question

I need to convert a string to an unsigned 32 bit integer (Cardinal).

In System.SysUtils unit there are many useful functions like:

StrToInt
StrToInt64
StrToUInt64

But I can't find any StrToCardinal, StrToUInt or StrToUInt32 function.

Why do you need one? Why isn't := StrToInt() enough for you? Have you encountered an actual problem? There also exists no StrToWord() and StrToByte()... — AmigoJack
– AmigoJack, Commented Jan 22, 2021 at 9:21
@AndreasRejbrand: I can't find it in my System.SysUtils (DelphiXE7), how is it implemented? — Fabrizio
– Fabrizio, Commented Jan 22, 2021 at 9:23
@AmigoJack: I know, but I have to work with Cardinal values (i.e: PIDs) — Fabrizio
– Fabrizio, Commented Jan 22, 2021 at 9:24
@Fabrizio: I suspected that. It merely converts the string to a 64-bit integer, checks if it is within a cardinal's range, and if so casts and if not raises an exception. It's a trivial three-liner. — Andreas Rejbrand
– Andreas Rejbrand, Commented Jan 22, 2021 at 9:25

fpiette · Accepted Answer · 2021-01-22 10:28:46Z

3

To follow Andreas Rejbrand idea posted as comment, I would suggest this:

function StrToCardinal(const S : String) : Cardinal;
var
    I64 : UInt64;
begin
    I64 := StrToUInt64(S);
    if (I64 shr 32) <> 0 then
        raise EConvertError.Create('StrToCardinal invalid value');
    Result := Cardinal(I64);
end;

answered Jan 22, 2021 at 10:28

fpiette

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4 Comments

Andreas Rejbrand Over a year ago

@AmigoJack: The OP said in the Q that StrToUInt64 exists. It's the third bullet in the list.

David Heffernan Over a year ago

@AndreasRejbrand docwiki.embarcadero.com/Libraries/Sydney/en/…

Andreas Rejbrand Over a year ago

@DavidHeffernan: I am afraid I don't quite see what you mean by giving that link. The OP already said that the function exists in XE7 and a link to the Sydney docs doesn't say much about the situation in XE7. Perhaps you meant to (1) give the link docwiki.embarcadero.com/Libraries/XE7/en/… and (2) address the comment to AmigoJack?

fpiette Over a year ago

@AmigoJack I tested my code with D10.4.1 and the OP said StrToUInt64 already existed at XE7 time.

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