Using an uninitialized structure
Regan Heath
regan at netmail.co.nz
Mon Sep 3 10:32:05 PDT 2007
B. Schulte wrote:
> Regan Heath Wrote:
>
>> B. Schulte wrote:
>>> Regan Heath Wrote:
>>>
>>>> B. Schulte wrote:
>>>>> Regan Heath Wrote:
>>>>>
>>>>>> Where is the definition of the CHAR_INFO structure? Have you defined it
>>>>>> in your code? eg.
>>>>>>
>>>>>> import std.c.windows.windows;
>>>>>>
>>>>>> extern(C)
>>>>>> {
>>>>>> struct CHAR_INFO {
>>>>>> union _Char {
>>>>>> WCHAR UnicodeChar;
>>>>>> CHAR AsciiChar;
>>>>>> }
>>>>>> _Char Char;
>>>>>> WORD Attributes;
>>>>>> }
>>>>>> alias CHAR_INFO* PCHAR_INFO;
>>>>>> }
>>>>>>
>>>>>> void main()
>>>>>> {
>>>>>> CHAR_INFO buffer[];
>>>>>> buffer.length = 100;
>>>>>> foreach( inout CHAR_INFO ci; buffer ) { ci.Char.AsciiChar = ' ';
>>>>>> ci.Attributes=7; }
>>>>>> }
>>>>>>
>>>>>> Regan
>>>>> Well, the CHAR_INFO structure is stored in the win32.wincon file. There was something I took from dsource to use the winAPI methods.
>>>>>
>>>>> I didn't want to write in orginal files to fix a problem. I thought about fixing the problem somewhere else. (Don't modify the wincon.d)
>>>>>
>>>>> However, it still doesn't work.
>>>>> Error 42: Symbol Undefined _D5win326wincon9CHAR_INFO6__initZ
>>>>>
>>>>>
>>>>> There must be some way to use uninitialized variables :(
>>>> There is, but I don't believe it has anything to do with the error
>>>> you're getting. :)
>>>>
>>>> You are missing a symbol, the symbol you are missing is mangled in such
>>>> a way that it is clear that it is a D symbol, which means you have
>>>> defined CHAR_INFO as a D struct, instead of using extern (C) as I have
>>>> shown you above.
>>>>
>>>> What dsource project is win32.wincon in? Perhaps CHAR_INFO isn't
>>>> declared as extern (C) in there...
>>>>
>>>> FYI, you can allocate an array of CHAR_INFO structures without
>>>> initialising like this:
>>>>
>>>> CHAR_INFO[500] abuffer = void;
>>>>
>>>> this is a fixed length array however, perhaps not what you want?
>>>>
>>>>
>>>> Regan
>>> Well, it really wasn't declared as extern(C). But I inserted it and declared it as extern(C). Don't know why, but it still don't work.
>>>
>>> Here is the dsource project:
>>> http://dsource.org/projects/core32
>> I can't see the win32.wincon file in the svn for that project:
>> http://dsource.org/projects/core32/browser/trunk/core32/win32
>>
>> I retract my comment about extern (C) I think maybe this has something
>> to do with how you're compiling it, the command line you're using.
>>
>> Regan
>
> Sorry, I was wrong. Here is the official Project page:
> http://www.prowiki.org/wiki4d/wiki.cgi?WindowsAPI
I thought it might be.
> However, here is my command line:
>
> compiling:
> dmd [files] -c -O -op -D -debug -version=WindowsXP
>
> linking:
> dmd [files]
This works for me:
[charinfo.d]
import std.c.windows.windows;
import win32.wincon;
void main()
{
CHAR_INFO[] buffer;
CHAR_INFO[500] abuffer = void;
buffer.length = 100;
foreach( inout CHAR_INFO ci; buffer ) { ci.Char.AsciiChar = ' ';
ci.Attributes=7; }
}
Compiled like so:
E:\D\src\tmp>dmd charinfo.d -c -O -op -D -debug -version=WindowsXP
E:\D\src\tmp>dmd e:\d\win32\win32\wincon.d -c -O -op -D -debug
-version=WindowsXP
E:\D\src\tmp>dmd charinfo.obj e:\d\win32\win32\wincon.obj
E:\D\dmd\bin\..\..\dm\bin\link.exe
charinfo+e:\d\win32\win32\wincon,,,user32+kernel32/noi;
Note, this fails giving the error you mentioned because I am not
compiling and linking with wincon.d:
E:\D\src\tmp>dmd charinfo.d
E:\D\dmd\bin\..\..\dm\bin\link.exe charinfo,,,user32+kernel32/noi;
OPTLINK (R) for Win32 Release 7.50B1
Copyright (C) Digital Mars 1989 - 2001 All Rights Reserved
charinfo.obj(charinfo)
Error 42: Symbol Undefined _D5win326wincon9CHAR_INFO6__initZ
--- errorlevel 1
If I include it in the compile and link, it works:
E:\D\src\tmp>dmd charinfo.d e:\d\win32\win32\wincon.d
E:\D\dmd\bin\..\..\dm\bin\link.exe charinfo+wincon,,,user32+kernel32/noi;
Regan
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