Re: [Lazarus] exception handling in constructor
On 02.03.2013 03:49, Xiangrong Fang wrote:
Hi there,
If my class constructor looks like this:
constructor TMyClass.Create(fn: string);
begin
sl := TStringList.Create;
try
fs := TFileStream.Create(fn, fmOpenRead);
except
self.Destroy;
end;
end;
No, this is a bad idea. If an exception occurs inside the constructor
the destructor will be called automatically. I don't even want to think
about what bad things could happen if you call Destroy inside the
constructor...
I create the objec like: MyInstance :=
TMyClass.Create('AnNonExistentFile'); An exception occured, I can
ensure that:
1. there is no memory leak.
There won't be a memory leak.
2. the MyInstance variable is assigned *nil*?
If you want to ensure that MyInstance is Nil you need to do it like this:
=== code begin ===
try
MyInstance := TMyClass.Create('AnNonExistentFile');
except
MyInstance := Nil;
end;
=== code end ===
Regards,
Sven
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Re: [Lazarus] exception handling in constructor
On 02/03/13 5:45, Flávio Etrusco wrote:
On Fri, Mar 1, 2013 at 11:49 PM, Xiangrong Fang wrote:
Hi there,
If my class constructor looks like this:
constructor TMyClass.Create(fn: string);
begin
sl := TStringList.Create;
try
fs := TFileStream.Create(fn, fmOpenRead);
except
self.Destroy;
end;
end;
I create the objec like: MyInstance :=
TMyClass.Create('AnNonExistentFile'); An exception occured, I can ensure
that:
1. there is no memory leak.
I assume FPC behaves like Delphi, so there's no leak.
Actually, you don't even need to explicitly call Destroy; when an
exception occurs in a constructor the destructor is called
automatically.
2. the MyInstance variable is assigned nil?
No, it's not initialized.
But you can write:
constructor TMyClass.Create(fn: string);
var fs: TFileStream;
begin
sl := TStringList.Create;
try
fs := TFileStream.Create(fn, fmOpenRead);
except
self:= nil;
end;
end;
which gives no memory leak, (provided your destructor frees the
stringlist sl) and also ensures MyInstance is assigned a nil value.
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Re: [Lazarus] exception handling in constructor
On Sat, 2 Mar 2013, Howard Page-Clark wrote:
On 02/03/13 5:45, Flávio Etrusco wrote:
On Fri, Mar 1, 2013 at 11:49 PM, Xiangrong Fang wrote:
Hi there,
If my class constructor looks like this:
constructor TMyClass.Create(fn: string);
begin
sl := TStringList.Create;
try
fs := TFileStream.Create(fn, fmOpenRead);
except
self.Destroy;
end;
end;
I create the objec like: MyInstance :=
TMyClass.Create('AnNonExistentFile'); An exception occured, I can ensure
that:
1. there is no memory leak.
I assume FPC behaves like Delphi, so there's no leak.
Actually, you don't even need to explicitly call Destroy; when an
exception occurs in a constructor the destructor is called
automatically.
2. the MyInstance variable is assigned nil?
No, it's not initialized.
But you can write:
constructor TMyClass.Create(fn: string);
var fs: TFileStream;
begin
sl := TStringList.Create;
try
fs := TFileStream.Create(fn, fmOpenRead);
except
self:= nil;
end;
end;
which gives no memory leak, (provided your destructor frees the stringlist
sl) and also ensures MyInstance is assigned a nil value.
This will definitely cause a memory leak, because the FPC code does
not know that an exception occurred in the constructor (you catch it with Except),
and hence will not call the destructor.
Heap dump by heaptrc unit
27 memory blocks allocated : 2067/2104
25 memory blocks freed : 1947/1984
2 unfreed memory blocks : 120
True heap size : 425984
True free heap : 425568
Should be : 425608
Call trace for block $7FEF86F892C0 size 104
$0041205C
$00411D4A
$00400283 line 15 of tm.pp
$004004CC line 30 of tm.pp
$0040018F
Call trace for block $7FEF86F810C0 size 16
$0041205C
$004001F7 line 14 of tm.pp
$004004CC line 30 of tm.pp
$0040018F
Also, setting Self to nil is nonsense.
If you do FreeAndNil(Self) instead, it will work.
But I would seriously warn against doing this kind of thing.
The idea of exceptions is exactly to let the exception propagate to callers,
so they know something is wrong. With the code as you propose,
MyInstance is nil, without any notification whatsoever that something went wrong or what exactly went wrong.
Michael.--
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Re: [Lazarus] Did anybody else use retinizer for Macbook Retina on lazarus before?
Hi Mattias, sorry that I did not answer your Post before today, somehow I did not see it. But as I saw in svn you managed to find it out by yourself, thank you for adding retina support to trunk! Michael Am 27.02.13 10:59, schrieb Mattias Gaertner: On Sun, 17 Feb 2013 20:45:07 +0100 Michael Ring wrote: The fonts of lazarus look very ugly on my Macbook Retina, a few weeks ago I found the tool retinizer http://retinizer.mikelpr.com/ and used it on lazarus, the results were amazing, very nice&crisp fonts! Nice. How does it achieve that? I would now like to create the necessary ressources for lazarus so that it uses retina out of the box without the need of using retinizer, main problem for me is that I do not use the graphical designer at all, I am using lazarus for embedded systems only, so I cannot really tell if switching lazarus to retina mode breaks anything in the GUI. Anybody else any experience ? Mattias -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] exception handling in constructor
On 02/03/13 10:51, Michael Van Canneyt wrote: This will definitely cause a memory leak, because the FPC code does not know that an exception occurred in the constructor (you catch it with Except), and hence will not call the destructor. Thanks for the correction and explanation. Howard -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
[Lazarus] Ok I give up!
Hi, How do you write the contents of a Memo to a file and read back into a Memo? I have tried all sorts, I am using Lazarus 1.0.6 on linux. How this started was because I wanted to write the content of my Memo to the clipboard and be able to paste it back in again, but I couldn't figure out how to do this in the linux version. Another thing how can I find out legal qualifiers i.e. Memo.Clear , Memo.Text (both illegal). What is legal? Thank you for any help Paul -- ---This message has been sent using Thunderbird on kubuntu--- -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] Ok I give up!
On 2-3-2013 13:05, appjaws wrote: > Hi, > How do you write the contents of a Memo to a file and read back into a > Memo? Memo1.Lines.SaveToFile Memo1.Lines.LoadFromFile > Another thing how can I find out legal qualifiers i.e. Memo.Clear , > Memo.Text (both illegal). What is legal? Type Memo. then press ctrl-space, then identifier completion will show you legal qualifiers. You can also go to the declaration of the tmemo (using alt-up) and see the source code to inspect the properties/methods/functions but as you'll see TMemo descends from TCustomMemo, probably inheriting some properties etc, and the inheritance tree goes on up. Finally, built in help is a nice aid: with your cursor on TMemo, press F1 and you'll see properties and methods that are available. There are probably more ways... -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] Ok I give up!
On Sat, 2 Mar 2013, appjaws wrote:
Hi,
How do you write the contents of a Memo to a file and read back into a Memo?
I have tried all sorts, I am using Lazarus 1.0.6 on linux.
Simple:
Memo1.Lines.SaveToFile('/home/yourname/yourfile.txt');
And
Memo1.Lines.LoadFromFile('/home/yourname/yourfile.txt');
How this started was because I wanted to write the content of my Memo to the
clipboard and be able to paste it back in again, but I couldn't figure out
how to do this in the linux version.
Another thing how can I find out legal qualifiers i.e. Memo.Clear , Memo.Text
(both illegal). What is legal?
Again, simple:
1. use code completion. Type
Memo.
Normally, if you wait ater typing the dot, the list of available qualifiers
will appear by itself after some time.
2. At least the published qualifiers are visible in the Object Inspector.
They are accessible in code with exactly the same names.
Michael.
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Re: [Lazarus] Ok I give up!
On Sat, Mar 2, 2013 at 2:05 PM, appjaws wrote: > Another thing how can I find out legal qualifiers i.e. Memo.Clear , > Memo.Text (both illegal). What is legal? See Memo.Lines. It has Clear and Text and everything that TStrings supports. How to find it? With a new component I usually look at its properties in Object Inspector, and use the code completion feature of the IDE to see available methods. Usually their names are intuitive and self documenting. For example Memo.Lines is pretty clear. If I don't find what I wanted then I must read documentation or use Google. Regards, Juha -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] exception handling in constructor
Sven Barth schrieb:
If you want to ensure that MyInstance is Nil you need to do it like this:
=== code begin ===
try
MyInstance := TMyClass.Create('AnNonExistentFile');
except
MyInstance := Nil;
end;
=== code end ===
When an exception occurs in Create, the assignment will never take
place. That's why MyInstance should be set to Nil *before* calling the
constructor. This also applies to memory leak protection of multiple
temporary objects:
inst1 := nil;
inst2 := nil;
...
try
inst1 := T1.Create;
inst2 := T2.Create;
...
finally
inst1.Free;
inst2.Free;
...
end;
The Free does no harm, even if the instances never were created, when
the variables are nil'ed before the try block.
DoDi
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Re: [Lazarus] Ok I give up!
Juha Manninen schrieb: On Sat, Mar 2, 2013 at 2:05 PM, appjaws wrote: Another thing how can I find out legal qualifiers i.e. Memo.Clear , Memo.Text (both illegal). What is legal? See Memo.Lines. It has Clear and Text and everything that TStrings supports. How to find it? With a new component I usually look at its properties in Object Inspector, and use the code completion feature of the IDE to see available methods. Usually their names are intuitive and self documenting. For example Memo.Lines is pretty clear. What is *not* clear, to the OP and many other users, that the required functionality is *not* found directly in TMemo, but resides in a property (.Lines) of it. In such cases code completion is of little help :-( DoDi -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] Ok I give up!
On 2-3-2013 13:54, Hans-Peter Diettrich wrote: > Juha Manninen schrieb: >> On Sat, Mar 2, 2013 at 2:05 PM, appjaws wrote: >>> Another thing how can I find out legal qualifiers i.e. Memo.Clear , >>> Memo.Text (both illegal). What is legal? >> >> See Memo.Lines. >> It has Clear and Text and everything that TStrings supports. > > What is *not* clear, to the OP and many other users, that the required > functionality is *not* found directly in TMemo, but resides in a > property (.Lines) of it. In such cases code completion is of little help > :-( True, but what other suggestion do you have apart from the ones already posted? -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
[Lazarus] Assignment on exception (was Re: exception handling in constructor)
Hi,
Could anyone explain this:
Number := 123;
try
Number := Ln(0);
except
end;
WriteLn(Number);
The output is *Nan*, not 123. i.e. when exception occurs the variable is
modified anyway! So in the example below assigning MyInstance to nil
before Create does not help to ensure it is nil if an exception occurs?
Thanks.
2013/3/2 Hans-Peter Diettrich
> Sven Barth schrieb:
>
>
> If you want to ensure that MyInstance is Nil you need to do it like this:
>>
>> === code begin ===
>>
>> try
>> MyInstance := TMyClass.Create('**AnNonExistentFile');
>> except
>> MyInstance := Nil;
>> end;
>>
>> === code end ===
>>
>
> When an exception occurs in Create, the assignment will never take place.
> That's why MyInstance should be set to Nil *before* calling the
> constructor. This also applies to memory leak protection of multiple
> temporary objects:
>
> inst1 := nil;
> inst2 := nil;
> ...
> try
> inst1 := T1.Create;
> inst2 := T2.Create;
> ...
> finally
> inst1.Free;
> inst2.Free;
> ...
> end;
>
> The Free does no harm, even if the instances never were created, when the
> variables are nil'ed before the try block.
>
> DoDi
>
>
>
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Re: [Lazarus] Ok I give up!
On Sat, 2 Mar 2013, Hans-Peter Diettrich wrote: Juha Manninen schrieb: On Sat, Mar 2, 2013 at 2:05 PM, appjaws wrote: Another thing how can I find out legal qualifiers i.e. Memo.Clear , Memo.Text (both illegal). What is legal? See Memo.Lines. It has Clear and Text and everything that TStrings supports. How to find it? With a new component I usually look at its properties in Object Inspector, and use the code completion feature of the IDE to see available methods. Usually their names are intuitive and self documenting. For example Memo.Lines is pretty clear. What is *not* clear, to the OP and many other users, that the required functionality is *not* found directly in TMemo, but resides in a property (.Lines) of it. In such cases code completion is of little help :-( You must learn the LCL or VCL. No amount of IDE help will ever take away that need. Yes, you must still study. It is inevitable. Luckily, there is a well-informed community which can provide answers quickly. As again demonstrated by the answers today. Michael. -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] Assignment on exception (was Re: exception handling in constructor)
On Sat, 2 Mar 2013, Xiangrong Fang wrote: Hi, Could anyone explain this: Number := 123; try Number := Ln(0); except end; WriteLn(Number); The output is Nan, not 123. i.e. when exception occurs the variable is modified anyway! So in the example below assigning MyInstance to nil before Create does not help to ensure it is nil if an exception occurs? It does, you can test that. I suspect that the case above is an artifact of the FPU error reporting, and it should be filed as a bug. Michael.-- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] Assignment on exception (was Re: exception handling in constructor)
I guess there is really a bug, see the following:
==
f := 123;
try
f := ln(0);
except
end;
//WriteLn(f);
//{
if f = 123 then
WriteLn('f=123, not modified')
else
WriteLn('f is modified to:', f);
//}
===
If I just WriteLn(f), it output Nan, I think there is some magic happening
here.
If I try to use if-then on f, then I get:
An unhandled exception occurred at $0040028C :
EDivByZero : Division by zero
$0040028C line 18 of project1.lpr
2013/3/2 Michael Van Canneyt
>
>
> On Sat, 2 Mar 2013, Xiangrong Fang wrote:
>
> Hi,
>>
>> Could anyone explain this:
>>
>> Number := 123;
>> try
>> Number := Ln(0);
>> except
>> end;
>> WriteLn(Number);
>>
>> The output is Nan, not 123. i.e. when exception occurs the variable is
>> modified anyway! So in the example below assigning MyInstance
>> to nil before Create does not help to ensure it is nil if an exception
>> occurs?
>>
>
> It does, you can test that.
>
> I suspect that the case above is an artifact of the FPU error reporting,
> and it should be filed as a bug.
>
> Michael.
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Re: [Lazarus] Assignment on exception (was Re: exception handling in constructor)
On 02.03.2013 14:04, Xiangrong Fang wrote: Hi, Could anyone explain this: Number := 123; try Number := Ln(0); except end; WriteLn(Number); The output is *Nan*, not 123. i.e. when exception occurs the variable is modified anyway! So in the example below assigning MyInstance to nil before Create does not help to ensure it is nil if an exception occurs? Because there is no exception. If you put a "Writeln" or something into the except block you'll see that no exception is raised. Additionally the "ln" is a compiler intrinsic. And as you give it a constant 0 the compiler will hardcode the "NaN" value instead of calculating it. The safest way in this case is to put the "Number := 123" into the "except" block (though in this specific example it wouldn't change anything). Regards, Sven -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] Assignment on exception (was Re: exception handling in constructor)
On Sat, 2 Mar 2013, Sven Barth wrote: On 02.03.2013 14:04, Xiangrong Fang wrote: Hi, Could anyone explain this: Number := 123; try Number := Ln(0); except end; WriteLn(Number); The output is *Nan*, not 123. i.e. when exception occurs the variable is modified anyway! So in the example below assigning MyInstance to nil before Create does not help to ensure it is nil if an exception occurs? Because there is no exception. If you put a "Writeln" or something into the except block you'll see that no exception is raised. Additionally the "ln" is a compiler intrinsic. And as you give it a constant 0 the compiler will hardcode the "NaN" value instead of calculating it. Hah, I had not thought of this. Indeed, assembler shows you are right :-) Michael. -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] Ok I give up!
On Sat, Mar 2, 2013 at 2:54 PM, Hans-Peter Diettrich wrote: > What is *not* clear, to the OP and many other users, that the required > functionality is *not* found directly in TMemo, but resides in a property > (.Lines) of it. In such cases code completion is of little help :-( Code completion finds the Lines property without problems. Juha -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] Ok I give up!
On 02/03/13 12:16, Reinier Olislagers wrote:
On 2-3-2013 13:05, appjaws wrote:
Hi,
How do you write the contents of a Memo to a file and read back into a
Memo?
Memo1.Lines.SaveToFile
Memo1.Lines.LoadFromFile
I tried the following line but I just get an error message :-
Call.pas(87,17) Error: Illegal qualifier
MemoCallNote.Lines.SaveToFile ('/home/paul/tmpinfo/MyTempFile.txt');
Another thing how can I find out legal qualifiers i.e. Memo.Clear ,
Memo.Text (both illegal). What is legal?
Type Memo. then press ctrl-space, then identifier completion will show
you legal qualifiers.
I didn't fine .Lines.SaveToFile?
You can also go to the declaration of the tmemo (using alt-up) and see
the source code to inspect the properties/methods/functions but as
you'll see TMemo descends from TCustomMemo, probably inheriting some
properties etc, and the inheritance tree goes on up.
Finally, built in help is a nice aid: with your cursor on TMemo, press
F1 and you'll see properties and methods that are available.
I don't think my built in help is working, F1 does nothing.
How do I enable built in help?
Thank you to all who responded
Paul
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Re: [Lazarus] Ok I give up!
On 2-3-2013 14:49, appjaws wrote:
> On 02/03/13 12:16, Reinier Olislagers wrote:
>> On 2-3-2013 13:05, appjaws wrote:
>>> Hi,
>>> How do you write the contents of a Memo to a file and read back into a
>>> Memo?
>> Memo1.Lines.SaveToFile
>> Memo1.Lines.LoadFromFile
>
> I tried the following line but I just get an error message :-
> Call.pas(87,17) Error: Illegal qualifier
>
> MemoCallNote.Lines.SaveToFile ('/home/paul/tmpinfo/MyTempFile.txt');
So is MemoCallNote a TMemo? What text is exactly at line 87, position 17?
If I drop a memo and a button on a form and assign this to the button's
OnClick event:
procedure TForm1.Button1Click(Sender: TObject);
begin
Memo1.Lines.SaveToFile('d:\cop\t\test.txt');
end;
... it works (on my windows machine - you'd obviously have to change the
path on Linux).
>>> Another thing how can I find out legal qualifiers i.e. Memo.Clear ,
>>> Memo.Text (both illegal). What is legal?
>> Type Memo. then press ctrl-space, then identifier completion will show
>> you legal qualifiers.
>
> I didn't fine .Lines.SaveToFile?
But did you find Lines? After Lines, do the same for .SaveToFile
I'm starting to suspect that what you think is a memo may not actually
be a memo.
If you want to, you can upload your project as a zip somewhere and I'll
have a look...
>> Finally, built in help is a nice aid: with your cursor on TMemo, press
>> F1 and you'll see properties and methods that are available.
>
> I don't think my built in help is working, F1 does nothing.
What version of Lazarus are you using - post 1.0 should have built in help.
> How do I enable built in help?
http://wiki.lazarus.freepascal.org/Installing_Help_in_the_IDE
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[Lazarus] ForceDirectoriesUTF8
Hi, In order to write cross platform programs, shall I use ForceDirectories or ForceDirectoriesUTF8? I would like to: - Use native charset on the platform (i.e. UTF8 on Linux and whatever codepage on Windows) - Avoid using AnsiString or the like (as all my programs use string type, change them all to AnsiString is scaring and I don't know the consequence at all). Thanks. -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] ForceDirectoriesUTF8
On 02.03.2013 15:12, Xiangrong Fang wrote:
* Avoid using AnsiString or the like (as all my programs use string
type, change them all to AnsiString is scaring and I don't know the
consequence at all).
Are your programs compiled in either {$mode Delphi} or {$mode
ObjFPC}{$H+}? If so then "String" = "AnsiString" already... (otherwise
String is equivalent to ShortString)
Regards,
Sven
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Re: [Lazarus] ForceDirectoriesUTF8
My program is always in {$mode objfpc} So string is not a problem, but
shall I use the UTF8 version or not? I remember that Windows is NOT UTF8?
2013/3/2 Sven Barth
> On 02.03.2013 15:12, Xiangrong Fang wrote:
>
>> * Avoid using AnsiString or the like (as all my programs use string
>>
>> type, change them all to AnsiString is scaring and I don't know the
>> consequence at all).
>>
>
> Are your programs compiled in either {$mode Delphi} or {$mode
> ObjFPC}{$H+}? If so then "String" = "AnsiString" already... (otherwise
> String is equivalent to ShortString)
>
> Regards,
> Sven
>
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Re: [Lazarus] Ok I give up!
On 2013-03-02 13:49:48 +, appjaws wrote:
> On 02/03/13 12:16, Reinier Olislagers wrote:
> >On 2-3-2013 13:05, appjaws wrote:
> >>Hi,
> >>How do you write the contents of a Memo to a file and read back into a
> >>Memo?
>
> MemoCallNote.Lines.SaveToFile ('/home/paul/tmpinfo/MyTempFile.txt');
>
Is there a space between SaveToFile and the opening parentheses?. Try
removing it.
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Re: [Lazarus] Ok I give up!
Reinier Olislagers schrieb: What is *not* clear, to the OP and many other users, that the required functionality is *not* found directly in TMemo, but resides in a property (.Lines) of it. In such cases code completion is of little help :-( True, but what other suggestion do you have apart from the ones already posted? Only the obvious one: add the frequently used TStrings methods also to TMemo. Either explicitly or in some more elegant way. E.g. the IStrings interface could be added to TMemo, implemented by Lines. That's the usual workaround for the lack of multiple inheritance, which here and in other list based controls would be the intuitive way for having both the list and control methods and properties in the class. DoDi -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] Ok I give up!
Juha Manninen schrieb: On Sat, Mar 2, 2013 at 2:54 PM, Hans-Peter Diettrich wrote: What is *not* clear, to the OP and many other users, that the required functionality is *not* found directly in TMemo, but resides in a property (.Lines) of it. In such cases code completion is of little help :-( Code completion finds the Lines property without problems. How is this helpful in finding the property, which finally implements Clear or some other task? DoDi -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] Ok I give up!
On 02.03.2013 15:57, Leonardo M. Ramé wrote:
On 2013-03-02 13:49:48 +, appjaws wrote:
On 02/03/13 12:16, Reinier Olislagers wrote:
On 2-3-2013 13:05, appjaws wrote:
Hi,
How do you write the contents of a Memo to a file and read back into a
Memo?
MemoCallNote.Lines.SaveToFile ('/home/paul/tmpinfo/MyTempFile.txt');
Is there a space between SaveToFile and the opening parentheses?. Try
removing it.
This should not make a difference...
Regards,
Sven
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Re: [Lazarus] Ok I give up!
On Sat, Mar 2, 2013 at 4:38 PM, Hans-Peter Diettrich wrote: >> Code completion finds the Lines property without problems. > > How is this helpful in finding the property, which finally implements Clear > or some other task? First you find Lines, then you find Clear. It is very helpful. :) Your idea of using interface for method delegation is actually good. It is actually the only elegant way to duplicate those methods on TMemo. I like the idea of extending LCL components instead of only imitating VCL like a monkey ... which brings us to FireMonkey ... Delphi itself moved to a more modern library design already. Using interfaces in a library requires proper design and thinking. Interfaces must be created for core functionality and injected to many classes. It is certainly doable. Java did it. Lots of effort is required to do it properly though. Regards, Juha -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] Ok I give up!
Any ideas on the built in help, I'm using linux with lazarus 1.0.6 and fpc 2.6.0 Finally, built in help is a nice aid: with your cursor on TMemo, press F1 and you'll see properties and methods that are available. I don't think my built in help is working, F1 does nothing. How do I enable built in help? Thank you to all who responded Paul -- ---This message has been sent using Thunderbird on kubuntu--- -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] Ok I give up!
> I don't think my built in help is working, F1 does nothing. How do I enable built in help? http://wiki.freepascal.org/Installing_Help_in_the_IDE -- View this message in context: http://free-pascal-lazarus.989080.n3.nabble.com/Lazarus-Ok-I-give-up-tp4029554p4029579.html Sent from the Free Pascal - Lazarus mailing list archive at Nabble.com. -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] ForceDirectoriesUTF8
> as all my programs use string type, change them all to AnsiString is
scaring and I don't know the consequence at all
Do you access the string's internal structure? Do you write the string to
file directly instead of taking its content? If not, then nothing you have
to worry about. Standard string operations work the same for all string
type.
> My program is always in {$mode objfpc} So string is not a problem, but
> shall I use the UTF8 version or not? I remember that Windows is NOT UTF8?
Windows supports wide characters, I don't know the encoding but it's likely
UTF-8 is at least in the subset. I suggest using UTF8 all the time.
1: You don't have to worry about it if in the future you need to support
UTF-8 characters
2: It does not hurt your current program
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Re: [Lazarus] Help with... help!
On 3/2/2013 00:20, Reinier Olislagers wrote: Guys, Anybody else interested in getting F1 to show the offline help if context-sensitive help is not appropriate? i followed a wiki page that the help points to... the only thing i'm not sure of is why it doesn't get built automatically when i update from SVN and build... i'll be working on something and then hit the F1 key and realize that the help stuff is being built... weird... I've gotten partway there but need some help: http://bugs.freepascal.org/view.php?id=23411 or... maybe i've misunderstood your goal above? -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] Ok I give up!
On 02/03/2013 13:49, appjaws wrote:
On 02/03/13 12:16, Reinier Olislagers wrote:
On 2-3-2013 13:05, appjaws wrote:
Hi,
How do you write the contents of a Memo to a file and read back into a
Memo?
Memo1.Lines.SaveToFile
Memo1.Lines.LoadFromFile
I tried the following line but I just get an error message :-
Call.pas(87,17) Error: Illegal qualifier
MemoCallNote.Lines.SaveToFile ('/home/paul/tmpinfo/MyTempFile.txt');
"MemoCallNote.Lines" is a TMemo on your form ( TForm1 )?
The above line of code is in a function or procedure that BELONGS to
TForm1 ?
That is a function or procedure like this
procedure TForm1.somename;
?
If it is in a function or procedure that does NOT have the name of
TForm1 in it, then it will not work.
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Re: [Lazarus] Ok I give up!
On 3/2/2013 07:54, Hans-Peter Diettrich wrote: What is *not* clear, to the OP and many other users, that the required functionality is *not* found directly in TMemo, but resides in a property (.Lines) of it. In such cases code completion is of little help :-( this is what i was going to write but you said it better than i could have... this has been the biggest problem i've faced in trying to move to this environment as well as learning the new routines and capabilities... it seems like every time i start digging about for a way to do something, i find that another of my self-built library tools i've used for years is already included... it seems that the more i dig, the less i need my own tools... but back to the above, yes... i wanted to do something similar as the OP, too... you'd think that memo.savetofile and memo.loadfromfile would be a natural thing and it would automatically do what needed to be done... -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] Ok I give up!
Hi Paul,
I'm going to respond to the list as well so they know what's going on.
On 2-3-2013 17:35, Paul wrote:
> Thank you Reinier for your offer to look at my code.I am new to Lazarus
> and am working through some delphi books to try and learn, but this has
> got me stumped.
> I tried a new form with Memo1 and used your code and it worked and the
> file was written to.
Normally it would be easier to send/upload both the .lfm and the .pas
file for the form - or better the entire project (easy via
project/publish project, then zip up the result - then you only include
relevant source files)
Also, saying what Lazarus version you're using normally helps...
That said, look at e.g.:
procedure TmpCut;
begin
MemoCallNote.Lines.SaveToFile(MyTempFile);
MemoCallNote.Clear;
end;
This is a regular procedure, not part of your form (the TFormCall object).
Without further changes, this code knows nothing about TFormCall,
including its MemoCallNote object. That's where the invalid qualifier
problems come from.
The easiest way to fix this is to move TmpCut to the private part of the
form:
interface
...
type
{ TFormCall }
TFormCall = class(TForm)
...
private
{ private declarations }
procedure TmpCut;
...
this declares a procedure TmpCut as part of the form... and it has
access to form properties etc.
However, you'll need to modify the procedure body from
procedure TmpCut;
to
procedure TFormCall.TmpCut;
to match the declaration above.
Note: all of this typed by hand, hope I did it ok.
Hope this is clear & it works for you.
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Re: [Lazarus] Help with... help!
On 2-3-2013 17:51, waldo kitty wrote: > On 3/2/2013 00:20, Reinier Olislagers wrote: >> Guys, >> >> Anybody else interested in getting F1 to show the offline help if >> context-sensitive help is not appropriate? > > i followed a wiki page that the help points to... the only thing i'm not > sure of is why it doesn't get built automatically when i update from SVN > and build... i'll be working on something and then hit the F1 key and > realize that the help stuff is being built... weird... The only thing that is built once is the lhelp executable. Having lhelp built when doing a make all or a lazbuild bigide would make sense IMO, yes, but is different from the issue I linked to. fpcup builds it for you ;)... ... but if you're using shell/batch scripts it's easy enough to do so, too. >> I've gotten partway there but need some help: >> http://bugs.freepascal.org/view.php?id=23411 > > or... maybe i've misunderstood your goal above? I think so, yes. I'm interested in getting a menu item that shows Help (not just Online Help) and having an F1 press result in getting lhelp with the table of contents/index/whatever up so a user can peruse the help - unless he's pressing F1 on an identifier, in which the current context-sensitive help can pop up as usual. -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] Ok I give up!
On 2-3-2013 17:41, appjaws wrote: > Any ideas on the built in help, I'm using linux with lazarus 1.0.6 and > fpc 2.6.0 > >>> Finally, built in help is a nice aid: with your cursor on TMemo, press >>> F1 and you'll see properties and methods that are available. > > I don't think my built in help is working, F1 does nothing. > How do I enable built in help? Well, did you read the wiki article I posted the link for? What happened? -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] Ok I give up!
On 02/03/13 17:21, Reinier Olislagers wrote: On 2-3-2013 17:41, appjaws wrote: Any ideas on the built in help, I'm using linux with lazarus 1.0.6 and fpc 2.6.0 Finally, built in help is a nice aid: with your cursor on TMemo, press F1 and you'll see properties and methods that are available. I don't think my built in help is working, F1 does nothing. How do I enable built in help? Well, did you read the wiki article I posted the link for? What happened? -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus Yes thank you I will have a go tomorrow. Paul -- ---This message has been sent using Thunderbird on kubuntu--- -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] Assignment on exception (was Re: exception handling in constructor)
On 3/2/2013 08:25, Xiangrong Fang wrote:
I guess there is really a bug, see the following:
==
f := 123;
try
f := ln(0);
except
end;
//WriteLn(f);
//{
if f = 123 then
WriteLn('f=123, not modified')
else
WriteLn('f is modified to:', f);
//}
===
If I just WriteLn(f), it output Nan, I think there is some magic happening here.
If I try to use if-then on f, then I get:
An unhandled exception occurred at $0040028C :
EDivByZero : Division by zero
$0040028C line 18 of project1.lpr
i am unable to reproduce this...
Lazarus 1.1 r39940 FPC 2.6.0 i386-win32-win32/win64
i started a new Simple Program project and pasted your above code into it...
C:\Documents and Settings\nil>LOCALS~1\Temp\project1
f=123, not modified
program Project1;
var
f : extended;
begin
f := 123;
try
f := ln(0);
except
end;
//WriteLn(f);
//{
if f = 123 then
WriteLn('f=123, not modified')
else
WriteLn('f is modified to:', f);
//}
end.
so i started a new Program project and again...
C:\Documents and Settings\nil>LOCALS~1\Temp\project1
f=123, not modified
program Project1;
{$mode objfpc}{$H+}
uses
{$IFDEF UNIX}{$IFDEF UseCThreads}
cthreads,
{$ENDIF}{$ENDIF}
Classes
{ you can add units after this };
var
f : extended;
begin
f := 123;
try
f := ln(0);
except
end;
//WriteLn(f);
//{
if f = 123 then
WriteLn('f=123, not modified')
else
WriteLn('f is modified to:', f);
//}
end.
what am i missing??
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Re: [Lazarus] Assignment on exception (was Re: exception handling in constructor)
On 02/03/13 19:34, waldo kitty wrote:
On 3/2/2013 08:25, Xiangrong Fang wrote:
I guess there is really a bug, see the following:
==
f := 123;
try
f := ln(0);
except
end;
//WriteLn(f);
//{
if f = 123 then
WriteLn('f=123, not modified')
else
WriteLn('f is modified to:', f);
//}
===
If I just WriteLn(f), it output Nan, I think there is some magic
happening here.
If I try to use if-then on f, then I get:
An unhandled exception occurred at $0040028C :
EDivByZero : Division by zero
$0040028C line 18 of project1.lpr
i am unable to reproduce this...
Lazarus 1.1 r39940 FPC 2.6.0 i386-win32-win32/win64
i started a new Simple Program project and pasted your above code into
it...
C:\Documents and Settings\nil>LOCALS~1\Temp\project1
f=123, not modified
program Project1;
var
f : extended;
begin
f := 123;
try
f := ln(0);
except
end;
//WriteLn(f);
//{
if f = 123 then
WriteLn('f=123, not modified')
else
WriteLn('f is modified to:', f);
//}
end.
so i started a new Program project and again...
C:\Documents and Settings\nil>LOCALS~1\Temp\project1
f=123, not modified
program Project1;
{$mode objfpc}{$H+}
uses
{$IFDEF UNIX}{$IFDEF UseCThreads}
cthreads,
{$ENDIF}{$ENDIF}
Classes
{ you can add units after this };
var
f : extended;
begin
f := 123;
try
f := ln(0);
except
end;
//WriteLn(f);
//{
if f = 123 then
WriteLn('f=123, not modified')
else
WriteLn('f is modified to:', f);
//}
end.
what am i missing??
Probably
http://wiki.freepascal.org/Multiplatform_Programming_Guide#Gtk2_and_masking_FPU_exceptions
Stephano
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Re: [Lazarus] Assignment on exception (was Re: exception handling in constructor)
On 3/2/2013 12:43, patspiper wrote: On 02/03/13 19:34, waldo kitty wrote: what am i missing?? Probably http://wiki.freepascal.org/Multiplatform_Programming_Guide#Gtk2_and_masking_FPU_exceptions the main thing i see there is that the sample uses the math unit... if this is what is necessary, then there is definitely some information missing from the problem description ;) i shall test again by adding the math unit to those two test projects... -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] Assignment on exception (was Re: exception handling in constructor)
On 3/2/2013 12:48, waldo kitty wrote: On 3/2/2013 12:43, patspiper wrote: On 02/03/13 19:34, waldo kitty wrote: what am i missing?? Probably http://wiki.freepascal.org/Multiplatform_Programming_Guide#Gtk2_and_masking_FPU_exceptions the main thing i see there is that the sample uses the math unit... if this is what is necessary, then there is definitely some information missing from the problem description ;) i shall test again by adding the math unit to those two test projects... never mind... my eyes were glazed and i didn't catch the widgetset reference to GTK2... after i had hit send on my previous, it struck me what you were actually pointing to and i had a much closer read... definitely some info missing from the original report :? -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] Photo camera and RFID devices
I was waiting some code examples. I have no expertise in these tecnologies you mentioned. SetCommDCB? DirectX? I have devices with camera and RFID readers builtin, and they aren't exactly the most recent models. From which SDK are you talking about? Every device with camera and/or RFID reader get these SDKs together? Are they prepared to generate pascal code? Excuse me if i don't have the very advanced knowledge you was expecting. But it seems to me that forums have people with various levels of expertise. Cheers Ricardo - Original Message - From: Anton Kavalenka Sent: 02/28/13 04:25 PM To: lazarus@lists.lazarus.freepascal.org Subject: Re: [Lazarus] Photo camera and RFID devices On 28.02.2013 21:27, "Arí Ricardo Ody" wrote: I have a program used for fixed assets field inventory. It runs in handhelds running windows mobile with ARM processors. I would like to know if someone here have used photo cameras and RFID readers/receivers in similar equipments. If affirmative should you explain how get access(and control) of the camera and the RFID reader/receiver, please? Greetings from São Paulo - Brazil Ricardo Dear Ricardo! WinCE is a windows from many points of view. So RFID reader - via serial port CreateFile() > SetCommDCB -> ReadFile ->Writefile -> Closehandle Camera - via DirectX IMO the control inteface with examples have to be expalined in your RFID-reader and Camera SDK. regards, Anton Kavalenka -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
[Lazarus] Accessing windows mobile handhelds from Lazarus programs
Some time a guy from the Lazarus team commented with me that I can use microsoft .NET DLLs from a Lazarus program. The idea I have is access SQLite databases recorded in a windows mobile handheld from a Lazarus program running in a PC computer. I know this is possible when try from a C# program. You can read/write SQLite databases direct in the handheld memory. I would like to know if someone here would have a pratical example of the code needed. Thanks in advance Greetingsfrom São Paulo - Brazil Ricardo -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] Ok I give up!
appjaws wrote: On 02/03/13 17:21, Reinier Olislagers wrote: On 2-3-2013 17:41, appjaws wrote: Any ideas on the built in help, I'm using linux with lazarus 1.0.6 and fpc 2.6.0 Finally, built in help is a nice aid: with your cursor on TMemo, press F1 and you'll see properties and methods that are available. I don't think my built in help is working, F1 does nothing. How do I enable built in help? Well, did you read the wiki article I posted the link for? What happened? Yes thank you I will have a go tomorrow. Paul Note that if you download the helpfiles manually, you might have to be careful of exactly where you put them: it's easy to have a situation you've unpacked them in a slightly different directory from where lhelp expects. -- Mark Morgan Lloyd markMLl .AT. telemetry.co .DOT. uk [Opinions above are the author's, not those of his employers or colleagues] -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] exception handling in constructor
On Sat, Mar 2, 2013 at 7:51 AM, Michael Van Canneyt wrote: > > > On Sat, 2 Mar 2013, Howard Page-Clark wrote: > >> On 02/03/13 5:45, Flávio Etrusco wrote: >>> >>> On Fri, Mar 1, 2013 at 11:49 PM, Xiangrong Fang wrote: (...) > > Also, setting Self to nil is nonsense. > > If you do FreeAndNil(Self) instead, it will work. > > But I would seriously warn against doing this kind of thing. Wow, this is unexpected. I always thougth that by definition a constructor would never return nil - so Self was a "by-value" parameter, even inside a constructor. Is this by design? I never saw the point of allowing assign to Self,... -Flávio -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] Maintainers: packages without description: please add them
--- El vie 1-mar-13, Reinier Olislagers escribió: > > lazreportpdfexport > Enables PDF export for lazreport (requires LazReport and > PowerPDF) > > lr_add_function > ? > Additional functions for lazreport (requires LazReport) > > lr_codereport_pkg > ? > > lr_dialogdesign > ? > > lr_sqldb > ? > > lr_tdbf > DBF database access component for lazreport (requires > LazReport) > > lr_zeosdb > Zeos database access component for lazreport (requires > LazReport) > Updated description on LazReport addon packages in r40462 Jesus Reyes A. -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] Ok I give up!
On Sat, Mar 2, 2013 at 11:36 AM, Hans-Peter Diettrich wrote: > Reinier Olislagers schrieb: > > >>> What is *not* clear, to the OP and many other users, that the required >>> functionality is *not* found directly in TMemo, but resides in a >>> property (.Lines) of it. In such cases code completion is of little help >>> :-( >> >> >> True, but what other suggestion do you have apart from the ones already >> posted? > > > Only the obvious one: add the frequently used TStrings methods also to > TMemo. Either explicitly or in some more elegant way. > > E.g. the IStrings interface could be added to TMemo, implemented by Lines. > That's the usual workaround for the lack of multiple inheritance, which here > and in other list based controls would be the intuitive way for having both > the list and control methods and properties in the class. > > DoDi > I might be wrong, but I guess it won't be very long before name clashes occur and this comfort and discoverability becomes a mess of confusing and ugly identifiers. IMO the correct fix, if it's indeed missing, would be documentation for TMemo wrt common usage. -Flávio -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] ForceDirectoriesUTF8
On 3/2/13, Xiangrong Fang wrote: > In order to write cross platform programs, shall I use ForceDirectories or > ForceDirectoriesUTF8? I would like to: I would think that that depends on where you get the value for ForceDirectories(UTF8) from. If this vale is obtained from any widget (OpenDialog, TEdit, etc.) the encoding of the value is in UTF-8. If however you get the value as a commandline parameter, then it is in system-encoding if you use ParamStr(), but in UTF-8 if you use ParamStrUTF8(). So you would use: Path := ParamStr(1); ForceDirectories(Path); or Path := SelectDirectoryDialog1.FileName; ForceDirectoriesUtf8(Path); You need to be sure which encoding a string has when you pass it on to such procedures/functions. Bart -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
[Lazarus] Did anybody else use retinizer for Macbook Retina on lazarus before?
Hi Mattias, sorry that I did not answer your Post before today, somehow I did not see it. But as I saw in svn you managed to find it out by yourself, thank you for adding retina support to trunk! Great! Is there any documentation available? Thank you, Johannes Michael Am 27.02.13 10:59, schrieb Mattias Gaertner: On Sun, 17 Feb 2013 20:45:07 +0100 Michael Ring wrote: The fonts of lazarus look very ugly on my Macbook Retina, a few weeks ago I found the tool retinizer http://retinizer.mikelpr.com/ and used it on lazarus, the results were amazing, very nice&crisp fonts! Nice. How does it achieve that? I would now like to create the necessary ressources for lazarus so that it uses retina out of the box without the need of using retinizer, main problem for me is that I do not use the graphical designer at all, I am using lazarus for embedded systems only, so I cannot really tell if switching lazarus to retina mode breaks anything in the GUI. Anybody else any experience ? Mattias -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- Dr. Johannes W. Dietrich, M.D. -- Laboratory XU44, Endocrine Research -- Medical Hospital I, Bergmannsheil University Hospitals -- Ruhr University of Bochum -- Buerkle-de-la-Camp-Platz 1, D-44789 Bochum, NRW, Germany -- Phone: +49:234:302-6400, Fax: +49:234:302-6403 -- eMail: "j.w.dietr...@medical-cybernetics.de" -- WWW: http://medical-cybernetics.de -- WWW: http://www.bergmannsheil.de -- Researcher ID: C-3498-2009 -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] ForceDirectoriesUTF8
> I would think that that depends on where you get the value for > ForceDirectories(UTF8) from. > If this vale is obtained from any widget (OpenDialog, TEdit, etc.) the > encoding of the value is in UTF-8. > If however you get the value as a commandline parameter, then it is in > system-encoding if you use ParamStr(), but in UTF-8 if you use > ParamStrUTF8(). That's what I guessed, so Instead of using UTF8 version I would use this to ensure cross platform correctness: Path := SelectDirectoryDialog1.FileName; ForceDirectories(UTF8Decode(Path)); Right? Yesterday I found in this post (which triggered me to ask the question initially): http://lists.lazarus.freepascal.org/pipermail/lazarus/2012-April/073170.html Such problems may (should) go away with the new Unicode- and AnsiString types, where AnsiString contains an Encoding field. Then the conversion between UTF-8 and the system codepage are done automatically, whenever required, and the xyUTF8 functions can be dropped then. If so, we shall avoid using **UTF8 functions at all. 2013/3/3 Bart > On 3/2/13, Xiangrong Fang wrote: > > > In order to write cross platform programs, shall I use ForceDirectories > or > > ForceDirectoriesUTF8? I would like to: > > I would think that that depends on where you get the value for > ForceDirectories(UTF8) from. > If this vale is obtained from any widget (OpenDialog, TEdit, etc.) the > encoding of the value is in UTF-8. > If however you get the value as a commandline parameter, then it is in > system-encoding if you use ParamStr(), but in UTF-8 if you use > ParamStrUTF8(). > > So you would use: > > Path := ParamStr(1); > ForceDirectories(Path); > > or > > Path := SelectDirectoryDialog1.FileName; > ForceDirectoriesUtf8(Path); > > You need to be sure which encoding a string has when you pass it on to > such procedures/functions. > > Bart > > -- > ___ > Lazarus mailing list > Lazarus@lists.lazarus.freepascal.org > http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus > -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
[Lazarus] "buffer" and string
Hi, I encountered unpredictable behavior with the following code: var fs: TFileStream; s: string; begin ... ... fs.Write(s, Length(s)); ... ... end; But if I do this, then problem is gone: var fs: TFileStream; s: string; buf: PChar; begin ... ... buf := GetMem(Length(s) + 1); StrPCopy(buf, s); fs.Write(buf^, Length(s)); ... ... end; My question is, why the above code with string works sometime, but not alwasy fail? What is the internal structure of string and variable array (i.e. array of something)? What is the difference between @string and @string[1] or @array and @array[0]? Thanks -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] Ok I give up!
On 3/2/2013 13:20, Mark Morgan Lloyd wrote: Note that if you download the helpfiles manually, you might have to be careful of exactly where you put them: it's easy to have a situation you've unpacked them in a slightly different directory from where lhelp expects. agreed... and if following the given instructions, things do work but files are not where they should apparently be... by that i mean that chm files are placed in html directory instead of chm directory or whatever the instructions call for... it was something i noticed a while back but never followed up on... -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] "buffer" and string
> My question is, why the above code with string works sometime, but not alwasy fail? TStream.Write expects a buffer, typically the first element of an item (NOT a pointer to it) and the length (number of elements after first one). > fs.Write(s, Length(s)); Here you try to give the WHOLE string, which is variable depending on the string type. It could be plain array for ShortString, but also pointer to a dynamically allocated structure for other strings. For ShortStrings, however, the above code will have the string length (if I'm not mistaken) before the first character in the written file. To do it correctly without converting to PChar is to give the first element: fs.Write(s[1], Length(s)); > What is the internal structure of string and variable array (i.e. array of > something)? Explained in docs: - static array: http://www.freepascal.org/docs-html/prog/progsu161.html#x204-2170008.2.9 - dynamic array: http://www.freepascal.org/docs-html/prog/progsu162.html#x205-2180008.2.10 - strings: http://www.freepascal.org/docs-html/prog/progsu159.html#x202-2120008.2.7 > What is the difference between @string and @string[1] or @array and > @array[0]? @string means pointer to to the string STRUCTURE, for ShortString, this is the same as @string[0] (the length) @string[1] means pointer to the first character in the string @array means pointer to the array STRUCTURE, for static array, this is the same as @array[] @array[0] means pointer to the element at index 0 -- View this message in context: http://free-pascal-lazarus.989080.n3.nabble.com/Lazarus-buffer-and-string-tp4029601p4029603.html Sent from the Free Pascal - Lazarus mailing list archive at Nabble.com. -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
Re: [Lazarus] "buffer" and string
If a buffer expect the first "element", and count is the number of elements to write, then what is the unit size of that element? is it always "byte"? 2013/3/3 leledumbo > > My question is, why the above code with string works sometime, but not > alwasy fail? > > TStream.Write expects a buffer, typically the first element of an item (NOT > a pointer to it) and the length (number of elements after first one). > > > fs.Write(s, Length(s)); > > Here you try to give the WHOLE string, which is variable depending on the > string type. It could be plain array for ShortString, but also pointer to a > dynamically allocated structure for other strings. For ShortStrings, > however, the above code will have the string length (if I'm not mistaken) > before the first character in the written file. > > To do it correctly without converting to PChar is to give the first > element: > > fs.Write(s[1], Length(s)); > > > What is the internal structure of string and variable array (i.e. array > of > > something)? > > Explained in docs: > - static array: > http://www.freepascal.org/docs-html/prog/progsu161.html#x204-2170008.2.9 > - dynamic array: > http://www.freepascal.org/docs-html/prog/progsu162.html#x205-2180008.2.10 > - strings: > http://www.freepascal.org/docs-html/prog/progsu159.html#x202-2120008.2.7 > > > What is the difference between @string and @string[1] or @array and > > @array[0]? > > @string means pointer to to the string STRUCTURE, for ShortString, this is > the same as @string[0] (the length) > @string[1] means pointer to the first character in the string > @array means pointer to the array STRUCTURE, for static array, this is the > same as @array[] > @array[0] means pointer to the element at index 0 > > > > > > -- > View this message in context: > http://free-pascal-lazarus.989080.n3.nabble.com/Lazarus-buffer-and-string-tp4029601p4029603.html > Sent from the Free Pascal - Lazarus mailing list archive at Nabble.com. > > -- > ___ > Lazarus mailing list > Lazarus@lists.lazarus.freepascal.org > http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus > -- ___ Lazarus mailing list Lazarus@lists.lazarus.freepascal.org http://lists.lazarus.freepascal.org/mailman/listinfo/lazarus
