Improve company productivity with a Business Account.Sign Up

x
  • Status: Solved
  • Priority: Medium
  • Security: Public
  • Views: 2360
  • Last Modified:

Delphi 2007 to Delphi 2010 (String, AnsiString and more)

Hello!

Me again =X
hehe

i like to do the things correctly and not just to silence the compiler =)

Using Delphi 2010, in a project made in Delphi 2007 a lot of bugs corrected...
Anyway, the typecast between String->PAnsiChar and back i have some doubts

example

function GetSomePath: String;
begin
  Result := 'C:\MyFolder\';
end;

WinExec(PAnsiChar(GetSomePath + 'SomeFile.exe'), SW_SHOWNORMAL);

Works but i got...
W1044 Suspicious typecast of string to PAnsiChar over PAnsiChar(GetSomePath)

To silence the compiler i can do

WinExec(PAnsiChar(AnsiString(GetSomePath) + 'SomeFile.exe'), SW_SHOWNORMAL);

But, i really don't know if its the right way... its not i think :S

Can somebody tell me the right way to TypeCast String, AnsiString, PChar, PAnsiChar with no data loss?

Best Regards,
Carlos
0
cebasso
Asked:
cebasso
  • 3
1 Solution
 
epasquierCommented:
>> WinExec(PAnsiChar(AnsiString(GetSomePath) + 'SomeFile.exe'), SW_SHOWNORMAL);

That is what the compiler does for you when you wrote the previous code (the one with warnings)

If you cast explicitly, the advantage is that the compiler does not complain, but the code is less readable...
Matter of choice, really, but the result is exactly the same (and as you said, both work)
0
 
epasquierCommented:
the best solution would be to create a GetSomePathA function , and call this one with WinExec.
As we said before, force the 'A' version when some API NEED Ansi

function GetSomePathA: ANSIString;
begin
 Result := 'C:\MyFolder\'; // always ANSI (that string is a path!!)
end;

function GetSomePathW: WideString;
begin
 Result := GetSomePathA; // always convert here
end;

function GetSomePath:String;
begin
 Result := GetSomePathA; // convertion will occur only with Delphi >2009
end;

Call :
 WinExec(PAnsiChar(GetSomePathA + 'SomeFile.exe'), SW_SHOWNORMAL);

in other places that do have to use ANSI, use the generic version :
 lblPath.Caption:=GetSomePath;

Open in new window

0
 
epasquierCommented:
One way to be sure if some extra conversion is done somewhere is to look at CPU code. Try with the examples above, with Delphi 2007 and 2009, you will see differences between GetSomePathW and GetSomePath, which codes are almost the same.
0
 
cebassoAuthor Commented:
Ahh ok!

So the best choice is really use a A version of many func/proc's like we said before...
:D
Thank you again!

Cheers!
0
Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

Join & Write a Comment

Featured Post

Free Tool: Path Explorer

An intuitive utility to help find the CSS path to UI elements on a webpage. These paths are used frequently in a variety of front-end development and QA automation tasks.

One of a set of tools we're offering as a way of saying thank you for being a part of the community.

  • 3
Tackle projects and never again get stuck behind a technical roadblock.
Join Now