[DUG] StrCopy problem

[Cameron Hart]

a := 'abcdefghixxxx';
b := 'jklmnopqr';
StrCopy(a,b);

You made source longer.  The dest needs to be strlen(source)+1

a := 'abcdefghi';
b := 'jklmnopqrxxxx';
StrCopy(a,b);



Cameron Hart


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From: delphi-bounces at listserver.123.net.nz [mailto:delphi-bounces at listserver.123.net.nz] On Behalf Of Ross Levis
Sent: Sunday, 12 May 2013 5:20 p.m.
To: 'NZ Borland Developers Group - Delphi List'
Subject: Re: [DUG] StrCopy problem

I did read that previously a few times.  Ok, so I should make A longer by 1 character?  I think A is already 10 characters long with a #0 at the end.

Anyway, I changed it to the following.
a := 'abcdefghixxxx';
b := 'jklmnopqr';
StrCopy(a,b);

Still an access violation in StrCopy.


From: delphi-bounces at listserver.123.net.nz<mailto:delphi-bounces at listserver.123.net.nz> [mailto:delphi-bounces at listserver.123.net.nz] On Behalf Of David Moorhouse
Sent: Sunday, 12 May 2013 3:26 PM
To: delphi at listserver.123.net.nz<mailto:delphi at listserver.123.net.nz>
Subject: Re: [DUG] StrCopy problem

Your answer is in the help file

Use StrCopy to copy Source to Dest. StrCopy returns Dest.

StrCpy does not perform any length checking. The destination buffer must have room for at least StrLen<http://docs.embarcadero.com/products/rad_studio/delphiAndcpp2009/HelpUpdate2/EN/html/delphivclwin32/SysUtils_StrLen@PAnsiChar.html>(Source)+1 characters.

For length checking, use the StrLCopy<http://docs.embarcadero.com/products/rad_studio/delphiAndcpp2009/HelpUpdate2/EN/html/delphivclwin32/SysUtils_StrLCopy@PAnsiChar@PAnsiChar@Cardinal.html> function.


D


On 12/05/13 14:45, Ross Levis wrote:
Doesn't really help.

a := 'abcdefghi' does allocate 9 bytes of RAM.  I can access a and b after it is assigned.  The problem is StrCopy crashes.  I would expect "a" to have the same string as b once this is executed.

Ross.

From: delphi-bounces at listserver.123.net.nz<mailto:delphi-bounces at listserver.123.net.nz> [mailto:delphi-bounces at listserver.123.net.nz] On Behalf Of Keith Allpress
Sent: Sunday, 12 May 2013 10:27 AM
To: 'NZ Borland Developers Group - Delphi List'
Subject: Re: [DUG] StrCopy problem

Perhaps:
http://rvelthuis.de/articles/articles-pchars.html


From: delphi-bounces at listserver.123.net.nz<mailto:delphi-bounces at listserver.123.net.nz> [mailto:delphi-bounces at listserver.123.net.nz] On Behalf Of Ross Levis
Sent: Sunday, 12 May 2013 2:39 a.m.
To: 'NZ Borland Developers Group - Delphi List'
Subject: [DUG] StrCopy problem

var
  a: pChar;
  b: pChar;
begin
  a := 'abcdefghi';
  b := 'jklmnopqr';
  StrCopy(a,b);
end;

Question:  Why does this code crash?




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