Mismatch in header notification definitions causes not-applicable
warnings
lazarus / 64-FPC development

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440bx · 2019-04-04 13:31

Hello,

The Header control notifications are defined as being negative
constants but, the NMHDR.code they are compared against is defined as
a longword.

This causes warnings from FPC. Specifically:

Warning: range check error while evaluating constants (-306 must be
between 0 and 4294967295)

This occurs for all the notification codes used by the header control.

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PascalDragon · 2019-04-05 07:14

Would you mind providing a bit more context, please? Cause right now
it isn't really clear what exactly you're talking about.

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Thaddy · 2019-04-05 07:55

NMHDR record member constants itself are declared as signed integers
(probably legacy) but the winapi NMHDR expects  longword members.
Hence the compiler barks.
(/win/wininc/struct.inc is correct, messages.inc isn't)

To suppress, cast to longword on use as a work-around.
Solution is possibly to redeclareCode: Pascal
 [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i const 
HDM_TESTDUMMY = longword(-321); // instead of HDM_TESTDUMMY =
-(321)var i:longint;    j:longword;   begin    i:=HDM_TESTDUMMY;  //
testlongword.pas(6,8) Warning: Range check error while evaluating
constants (4294966975 must be between -2147483648 and 2147483647)   
j:=HDM_TESTDUMMY;  // OK.    writeln(i,'|',j);end.Is that enough
context?
[edit]
reported in Mantis as #0035324

p.s. the example actually reverses the issue to make it clear.

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ASerge · 2019-04-05 18:13

For clarification.
SDK defines such const as unsigned (commctrl.h):
Code: C  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i #define
HDN_FIRST               (0U-300U)       // headerBut FPC as signed
(commctrl.pp)
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i HDN_FIRST 
                   = (0-300);          // headerSo it will be enough
to specify
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i HDN_FIRST 
                   = LongWord(0-300);          // header

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440bx · 2019-04-05 18:34

Quote from: ASerge on April 05, 2019, 08:13:28 pmCode: Pascal
 [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i HDN_FIRST 
                   = (0-300);          // headerSo it will be enough
to specify
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i HDN_FIRST 
                   = LongWord(0-300);          // headerYes,
fortunately, it is a very simple thing to fix.

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Thaddy · 2019-04-05 19:30

Yes. As I showed before ASerge. Aside: it is indeed legacy..