understanding that SearchRec has different formats for different OS targets, we've tried to use fillchar to initialize it to an empty record... unfortunately that does not remove the hint... instead the hint points to the fillchar line...

we do not want to turn off hints so how can we initialize dirinfo and make fpc happy?

[quote="os/2 ecs"]
Hint: Start of reading config file fpc.cfg
Hint: End of reading config file fpc.cfg
Free Pascal Compiler version 2.6.2 [2013/02/09] for i386 Copyright (c) 1993-2012 by Florian Klaempfl and others Target OS: OS/2
Compiling dirinfo.pas
dirinfo.pas(13,19) Hint: Variable "dirinfo" does not seem to be initialized Assembling test_searchrec
Linking dirinfo.exe
emxbind 0.9d -- Copyright (c) 1991-1997 by Eberhard Mattes Deleting *path*\projects\satsort\dirinfo.out
1 file deleted 335,872 bytes freed
16 lines compiled, 3.9 sec
3 hint(s) issued
[/quote]

[quote]="vista"]
C:\freepascal\projects\misc_projects>fpc -vhinw dirinfo.pas Hint: Start of reading config file fpc.cfg
Hint: End of reading config file fpc.cfg
Free Pascal Compiler version 2.7.1 [2013/12/05] for i386 Copyright (c) 1993-2013 by Florian Klaempfl and others Target OS: Win32 for i386
Compiling dirinfo.pas
dirinfo.pas(13,19) Hint: Variable "dirinfo" does not seem to be initialized Linking dirinfo.exe
16 lines compiled, 0.8 sec, 28304 bytes code, 1524 bytes data 3 hint(s) issued
[/quote]

[quote="dirinfo.pas"]
program test_SearchRec;
uses
   Dos;
const
   pattern : string = '*.pas';
var
   dirinfo : SearchRec;
begin
   fillchar(dirinfo,sizeof(dirinfo),$00);
   FindFirst(pattern,AnyFile,dirinfo);
   findclose(dirinfo);
end.
[/quote]

waldo kitty wrote

understanding that SearchRec has different formats for different OS targets, we've tried to use fillchar to initialize it to an empty record... unfortunately that does not remove the hint... instead the hint points to the fillchar line...

It is virtually impossible to get a realistic program free of any hints. Hints are the lowest possible verbosity level and their only goal is to help you pinpoint extremely unlikely sources of problems if you've exhausted all other options. They cause false positives by design (in this case: passing an uninitialized variable to a var-parameter; and since fillchar's first parameter is such a parameter and cannot be changed to "out" for reasons discussed many times before on this list, using that routine indeed does not help).

Jonas

With 2.7+ you can use Default (in objfpc mode):

  dirinfo:=Default(SearchRec);

Beginning with 2.7.1 you can use the new Default() intrinsic which takes a type name as first and only argument (it returns a 0 initialized value of that type):

=== code begin ===

var
   dirinfo: SearchRec;
begin
   dirinfo := Default(SearchRec);
   FindFirst(pattern, AnyFile, dirinfo);
   FindClose(dirinfo);
end;

=== code end ===

Regards,
Sven

Sorry for quoting the whole message... hit the wrong key *blush*

Regards,
Sven

It does not need mode ObjFPC, Default() is supported in any mode (as it's a "system magic function" like Length(), High(), etc..

Regards,
Sven

Out of curiosity, does this work:

var
    dirinfo: SearchRec= Default(SearchRec);

Sven Barth wrote

Beginning with 2.7.1 you can use the new Default() intrinsic which takes a type name as first and only argument (it returns a 0 initialized value of that type):

2.7.1 which means that we still have to respond to queries with older versions... ok, i think we can deal with that...

+1 ;)

what i run into is porting old code and trying to possbly also make it multi-platform... the biggest gotcha we've run into is those typed constants that are used to hold values between executions of a routine... those should be initialized to a zero/empty value before first execution but then retain their values afterward...

waldo kitty wrote

we do not want to turn off hints so how can we initialize dirinfo and make fpc happy?

I hate such hints too! This is what I did in my code to prevent that unwanted hint.

One part is the usage of an out parameter, and the second part is the
{$HINT OFF} directive.
----8<-------------8<-------------8<-------------8<-------------8<----
program test_SearchRec;
uses
   Dos;
const
   pattern : string = '*.pas';
var
   dirinfo : SearchRec;
// prevents the compiler hint about not initialized variables
procedure dcpFillChar(out x; count: SizeInt; Value: Byte);
begin
  {$HINTS OFF}
  FillChar(x, count, value);
  {$HINTS ON}
end;
begin
   dcpFillchar(dirinfo,sizeof(dirinfo),$00);
   FindFirst(pattern,AnyFile,dirinfo);
   findclose(dirinfo);
end.
----8<-------------8<-------------8<-------------8<-------------8<----

And here is the compiler output:

[tmp]$ fpc -viwnh test_SearchRec.pas
Hint: Start of reading config file /home/graemeg/.fpc.cfg Hint: End of reading config file /home/graemeg/.fpc.cfg Free Pascal Compiler version 2.6.2 [2013/02/10] for x86_64 Copyright (c) 1993-2012 by Florian Klaempfl and others Target OS: FreeBSD for x86-64
Compiling test_SearchRec.pas
Linking test_SearchRec
25 lines compiled, 0.0 sec
2 hint(s) issued

Regards,
- Graeme -

Not yet. It's on my ToDo list however since I implemented Default().

Regards,
Sven

That would be useful. I'm currently trying to do a line-by-line transcription of a CPU emulator that somebody's been misguided enough to write in JavaScript. Being able to deal concisely with things like

this.memMod = [ // Array of memory module words as Float64s (8 x 4KW each)

         null, null, null, null, null, null, null, null];

would be a decided advantage.

Am 03.01.2014 08:36 schrieb "Mark Morgan Lloyd" <

transcription of a CPU emulator that somebody's been misguided enough to write in JavaScript. Being able to deal concisely with things like

this.memMod = [ // Array of memory module words as Float64s (8 x 4KW

each)

null, null, null, null, null, null, null, null]; would be a decided advantage.

In case of arrays you can already do the following:

=== code begin ===

const
  NullMemMod: array[0..7] of Pointer(* or whatever *) = (Nil, Nil, Nil,
Nil, Nil, Nil, Nil, Nil);
// somewhere else:
Self.MemMod := NullMemMod;

=== code end ===

Regards,
Sven

"Graeme Geldenhuys" wrote

On 2014-01-02 19:21, waldo kitty wrote: > > we do not want to turn off hints so how can we initialize dirinfo and

make fpc

I would suggest to use the following sequence instead:

=== code begin ===

{$push}
{$hints off}
// whatever
{$pop}

=== code end ===

This way if the hints are switched off before that code is reached they will stay off afterwards instead of being switched on.

Regards,
Sven

I would suggest to use the following sequence instead:
=== code begin ===
{$push}
{$hints off}
// whatever
{$pop}
=== code end ===
  The is a more specific way to remove a given hint:

Use -vq option to get the numeric value of the message:

E:\pas\test>ppc386 -vhq tsearchrec.pas
Hint: (11030) Start of reading config file
e:\pas\fpc-2.7.1\bin\i386-win32\fpc.cfg
Hint: (11031) End of reading config file
e:\pas\fpc-2.7.1\bin\i386-win32\fpc.cfg
tsearchrec.pas(13,20) Hint: (5058) Variable "dirinfo" does not seem to be initialized

Disable that specific message by using -vm option:

E:\pas\test>ppc386 -vh -vm5058 tsearchrec.pas
Hint: Start of reading config file e:\pas\fpc-2.7.1\bin\i386-win32\fpc.cfg Hint: End of reading config file e:\pas\fpc-2.7.1\bin\i386-win32\fpc.cfg

Magic, isn't it?

Pierre Muller

Maybe one should also mention that this can be done in code as well for specific locations:

=== code begin ===
{$push}
{$warn 5058 off}
// whatever
{$pop}
=== code end ===

Regards,
Sven

It seems it can be made still easier by right-clicking on the message in the message window and by selecting "Hide message via directive". Then a {%H-} is appended to the variable that caused the message which does not add additional lines of code.

Sven Barth wrote

This way if the hints are switched off before that code is reached they will stay off afterwards instead of being switched on.

Interesting, thanks for the tip.

Regards,
- Graeme -

"Jürgen Hestermann" wrote

Am 2014-01-03 12:07, schrieb Sven Barth: > Maybe one should also mention that this can be done in code as well for

specific locations:

This only works inside Lazarus and only tells the IDE to ignore hints from that position (roughly). If you compile on the command line the hint will resurface. Also it does not seem that one is able to control which type of hint is hidden.

Regards,
Sven

(Sending again: the mailserver bounced it the first time.)

Jürgen Hestermann wrote

It seems it can be made still easier by right-clicking on the message in the message window and by selecting "Hide message via directive". Then a {%H-} is appended to the variable that caused the message which does not add additional lines of code.

That's a Lazarus thing isn't it?
AFAIK it doen't suppress the compiler hint, it just doesn't show it in the Messages window.

Bart

following up on this... this is what i came up with... is it right/proper?

   {$IF (FPC_FULLVERSION >= 20701)}
   {$INFO initializing dirinfo with Default(SearchRec)}
   dirinfo := default(searchrec);
   {$ELSE}
   {$PUSH}
   {$HINTS OFF}
   {$INFO initializing dirinfo with fillchar(dirinfo,sizeof(dirinfo),$00)}
   fillchar(dirinfo,sizeof(dirinfo),$00);
   {$POP}
   {$ENDIF}

Should be correct.

Regards,
Sven

thanks! it seems to work on the few systems where i tested it... we have to ensure that we get it placed into our existing code base ;)