Lazarus with FPC3.0 without UTF-8 mode: what changed

Revision 0 to 1. Removed lines have a minus sign; added lines have a plus sign.

Title: Lazarus with FPC3.0 without UTF-8 mode

New		Line
1	+	This page explains the problems and their possible solutions when using Lazarus with FPC 3.0+ but without the new UTF-8 mode. It may be needed when big parts of program code depend on system codepage. The UTF-8 mode is explained here:
2	+
3	+	- [[Unicode Support in Lazarus]]
4	+
5	+	To disable the new UTF-8 mode, -dDisableUTF8RTL must be defined in project options, "Additions and Overrides" page. There is a button "Use system encoding" to help adding it with one click. This way it affects both the project and all its dependent packages, including LazUtils which contains the relevant code. If you use strings with codepoints \> 127 in your project, you have to change the file encoding to the system encoding too.
6	+
7	+	Bart has collected some reported issues under a meta-issue. Fortunately most of them are solved and Lazarus libraries should be robust also without the UTF-8 mode. There is an unsolved FPC issue about RawByteString though.
8	+
9	+	- <http://bugs.freepascal.org/view.php?id=28857>
10	+
11	+	# Simple Example
12	+
13	+	- create a New Project -\> Simple Program
14	+	- activate the -dDisableUTF8RTL mode with Project Options ... -\> Compiler Options -\> Additions and Overrides -\> click on Use system encoding
15	+	- change the file encoding: Source Editor -\> mouse rightclick -\> File Settings -\> Encoding -\> take your system encoding (for that example take 1252) and confirm
16	+
17	+	Now you are able to build a project without UTF8 dependences.
18	+
19	+	Write something in your source editor:
20	+
21	+	``` pascal
22	+	program project1;
23	+
24	+	{$mode objfpc}{$H+}
25	+	{$codepage cp1252}
26	+
27	+	var
28	+	test: String;
29	+
30	+	begin
31	+	test := 'ÄÖÜ';
32	+	WriteLn(test);
33	+	ReadLn;
34	+	end.
35	+	```
36	+
37	+	Start your program.
38	+
39	+	## Problem System encoding and Console encoding (Windows)
40	+
41	+	If you start the simple example, you will maybe see a wrong content for that `writeln('ÄÖÜ')`. This is because you can have different codepages for the console and the file system. To check which codepage you have you can make a simple test:
42	+
43	+	``` pascal
44	+	Writeln('Console output codepage: ', GetTextCodePage(Output));
45	+	Writeln('System codepage: ', DefaultSystemCodePage);
46	+	```
47	+
48	+	If your console codepage is different from your system codepage, you can change it in that way (original code from [forum](http://forum.lazarus.freepascal.org/index.php/topic,30200.msg191843.html#msg191843))
49	+
50	+	``` pascal
51	+	unit setdefaultcodepages;
52	+
53	+	interface
54	+
55	+	uses
56	+	Windows;
57	+
58	+	implementation
59	+
60	+	Const
61	+	LF_FACESIZE = 32;
62	+
63	+	Type
64	+	CONSOLE_FONT_INFOEX = record
65	+	cbSize : ULONG;
66	+	nFont : DWORD;
67	+	dwFontSize : COORD;
68	+	FontFamily : UINT;
69	+	FontWeight : UINT;
70	+	FaceName : array [0..LF_FACESIZE-1] of WCHAR;
71	+	end;
72	+
73	+	{ Only supported in Vista and onwards!}
74	+
75	+	function SetCurrentConsoleFontEx(hConsoleOutput: HANDLE; bMaximumWindow: BOOL; var CONSOLE_FONT_INFOEX): BOOL; stdcall; external kernel32;
76	+
77	+	var
78	+	New_CONSOLE_FONT_INFOEX: CONSOLE_FONT_INFOEX;
79	+
80	+	initialization
81	+	SetConsoleOutputCP(DefaultSystemCodePage);
82	+	SetTextCodePage(Output, DefaultSystemCodePage);
83	+
84	+	FillChar(New_CONSOLE_FONT_INFOEX, SizeOf(CONSOLE_FONT_INFOEX), 0);
85	+	New_CONSOLE_FONT_INFOEX.cbSize := SizeOf(CONSOLE_FONT_INFOEX);
86	+	New_CONSOLE_FONT_INFOEX.FaceName := 'Consolas';
87	+	// New_CONSOLE_FONT_INFOEX.FaceName := 'Lucida Console'; //use Lucida Console for Win XP
88	+	New_CONSOLE_FONT_INFOEX.FontWeight := 400;
89	+	New_CONSOLE_FONT_INFOEX.dwFontSize.Y := 16;
90	+
91	+	SetCurrentConsoleFontEx(StdOutputHandle, False, New_CONSOLE_FONT_INFOEX);
92	+	end.
93	+	```
94	+
95	+	If you now build a project and use that unit, all strings are correctly shown (Strings also Shortstrings). For example:
96	+
97	+	``` pascal
98	+	program project1;
99	+
100	+	{$mode objfpc}{$H+}
101	+	{$codepage cp1252}
102	+
103	+	uses
104	+	setdefaultcodepages;
105	+
106	+	const
107	+	StrCP1252 = #$80#$C4#$D6#$8C#$A5;
108	+
109	+	var
110	+	AStr : String;
111	+	AShortString : ShortString;
112	+	begin
113	+	AStr := StrCP1252;
114	+	AShortString := StrCP1252;
115	+	WriteLn(StrCP1252);
116	+	WriteLn('€ÄÖŒ¥');
117	+	WriteLn(AStr);
118	+	WriteLn(AShortString);
119	+	ReadLn;
120	+	end.
121	+	```
122	+
123	+	# Problem applications with ACP strings and LCL controls
124	+
125	+	If you want to use some LCL controls like TLabel, TEdit, TMemo etc., you have to convert the strings, cause the LCL controls use the UTF8 strings further. You can use the method SysToUTF8 for the conversion of a string to a LCL control string and UTF8ToSys for the conversion back.
126	+
127	+	## Example
128	+
129	+	- create a new Project Application and change the encoding of your project file to CP1252 and activate the -dDisableUTF8RTL mode
130	+	- add a TEdit and a TButton on the form
131	+	- create the event handler for the button click and write this code:
132	+
133	+	``` pascal
134	+	procedure TForm1.Button1Click(Sender: TObject);
135	+	var
136	+	s: String;
137	+	begin
138	+	s := 'Läuse und Flöhe';
139	+	Edit1.Text := SysToUTF8(s);
140	+	end;
141	+	```
142	+
143	+	---
144	+	From the Free Pascal wiki, page "Lazarus with FPC3.0 without UTF-8 mode", as it stood on 2020-02-18 after a change by Trev, out of the wiki's dump of 2024-05-26. Copyright stays with the author who wrote it, according to the old wiki's [[Licensing]] page. If you have concerns about this material, [message the admin](/wiki-contact).
145	+	Category: FPC 3.0+ stuff
146	+	Category: Unicode

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