DelteFile function - UnicodeString expected PChar

[Int3g3r]

Hello

Can someone explain to me why it is so difficult to delete a file if you have the path? 
I can't, and I don't know why.

First (see image), why does autocomplete first show the DeleteFile() function with LPCSTR.
If i chose it, i get now RawByteString oder UnicodeString?

Second. How do i delete a file, this can't be that hard.

What is wrong here?

dm_main.pas(102,39) Error: Incompatible type for arg no. 1: Got "UnicodeString", expected "PChar"

Code: Pascal  [Select][+][-]

1. uses
2.   Classes, SysUtils, Dialogs, Windows, LazFileUtils, LR_DBSet, LR_Class,
3.   LR_Desgn, lr_e_pdf, uResource, uini, DB, ZConnection, ZSqlProcessor, ZDataset,
4.   ZAbstractRODataset, DBCtrls, fileutil, LazUtf8;
5.  
6. //.....
7.  
8. procedure TdmMain.DataModuleCreate(Sender: TObject);
9. var
10.   tempDirectoryPath: String;
11.   files: TStringList;
12.   item: String;
13. begin
14.   tempDirectoryPath := ExtractFilePath(ParamStr(0))+'temp';
15.   if not DirectoryExists(tempDirectoryPath) then
16.   begin
17.    CreateDir(tempDirectoryPath);
18.   end
19.   else
20.   begin
21.      try
22.        files := TStringList.Create;
23.        files := FindAllFiles(tempDirectoryPath,'*.*',true);
24.        for item in files do
25.        begin
26.           ShowMessage(item);
27.           DeleteFile(UTF8ToUTF16(item));
28.        end;
29.      finally
30.        files.Free;
31.      end;
32.   end;
33. end;    
34.  

I have created a new project and it works. 
I do not understand.

Code: Pascal  [Select][+][-]

1. uses
2.    FileUtil, LazUtf8
3.  
4. //...
5.  
6. procedure TformMain.btnGenerateClick(Sender: TObject);
7. var
8.    path: String;
9.    files: TStringList;
10.    item: String;
11. begin
12.    path:= 'C:\Temp';
13.    try
14.      files := TStringList.Create;
15.      files := FindAllFiles(path,'*.*',false);
16.      for item in files do
17.      begin
18.        ShowMessage(item);
19.        DeleteFile(UTF8ToUTF16(item));
20.      end;
21.    finally
22.      files.Free;
23.    end;
24. end;    
25.  

Regards Int3g3r

[Nimbus]

One with LPCSTR comes from Windows unit which you have on the uses list. One you probably want is from SysUtils, you can try calling explicitly, e.g.

Code: Pascal  [Select][+][-]

1. SysUtils.DeleteFile(item);

[Int3g3r]

One with LPCSTR comes from Windows unit which you have on the uses list. One you probably want is from SysUtils, you can try calling explicitly, e.g.

Code: Pascal  [Select][+][-]

1. SysUtils.DeleteFile(item);

Thank you very much !!!

Why does Lazarus not recognize that i want the function from SysUtils?
Why do i have to specify it?
Is this not clear if i pass a "UnicodeString" ?

Regards Int3g3r

[Zvoni]

Why does Lazarus not recognize that i want the function from SysUtils?
Why do i have to specify it?
Is this not clear if i pass a "UnicodeString" ?

Regards Int3g3r

Because FPC/Lazarus RESPECTS the Order of Units included in the Uses-Clause, the "last" one winning the race.
So if your SysUtils is BEFORE the Windows-unit in Uses, Windows wins

[Int3g3r]

Because FPC/Lazarus RESPECTS the Order of Units included in the Uses-Clause, the "last" one winning the race.
So if your SysUtils is BEFORE the Windows-unit in Uses, Windows wins

Perfect, Thank you 

[WooBean]

Because FPC/Lazarus RESPECTS the Order of Units included in the Uses-Clause, the "last" one winning the race.
So if your SysUtils is BEFORE the Windows-unit in Uses, Windows wins

It may be surprising but when units (or generally source names) are dotted the rule becomes more complicated.
At this case at first is searched the longest (in dots number) fitting dotted source name (including a program, a library, a package or units).

Nobody had promissed that all will be simple, and then kept his word.

[PascalDragon]

Why does Lazarus not recognize that i want the function from SysUtils?
Why do i have to specify it?
Is this not clear if i pass a "UnicodeString" ?

DeleteFile (no matter if SysUtils or Windows) is not declared as overload, thus the compiler stops searching for possible candidates once it found the first candidate without overload. This is part of the language rules. As others wrote you can enforce this by explicitly providing the unit name.

(And no, we have no desire to add overload to each and everything)

Because FPC/Lazarus RESPECTS the Order of Units included in the Uses-Clause, the "last" one winning the race.
So if your SysUtils is BEFORE the Windows-unit in Uses, Windows wins

It may be surprising but when units (or generally source names) are dotted the rule becomes more complicated.
At this case at first is searched the longest (in dots number) fitting dotted source name (including a program, a library, a package or units).

For an identifier without any unit or namespace identifier there is no difference.