On 01/10/2011 08:13, Mattias Gaertner wrote:
On Sat, 1 Oct 2011 10:08:59 +0300
Zaher Dirkey<[email protected]> wrote:
Off your topic
On Sat, Oct 1, 2011 at 9:53 AM, Mattias Gaertner
<[email protected]>wrote:
"Assigned" is used instead of "FOnClick<>nil"
What is different between check the Method fields ?
"Assigned(FOnClick)" and "FOnClick<>nil"
http://wiki.lazarus.freepascal.org/IDE_tricks#Events_.28Method_properties.29_in_the_Object_Inspector
Strange, on the page it says:
if OnMyEvent<> nil then OnMyEvent(...);// wrong, because it checks Data too
if OnMyEvent = NewValuethen exit;// wrong, because it compares only Code
So I compiled (to assembler) 32 bit:
Comparison with nil (expect to check code + data, as told above)
Comparison with other method (expect code only)
But in both cases it tests one long entry (testl or cmpll). so the same
amount of data. It doesn't look that <> nil checks code+data?
# [33] if OnDeactivate <> nil then;
movl -8(%ebp),%eax
movl 980(%eax),%eax
testl %eax,%eax
.Lj6:
.Ll3:
# [34] if OnClose = nil then;
movl -8(%ebp),%eax
movl 956(%eax),%eax
testl %eax,%eax
.Lj8:
.Ll4:
# [35] if OnDeactivate = OnCreate then;
movl -8(%ebp),%eax
movl -8(%ebp),%edx
movl 980(%eax),%eax
cmpl 972(%edx),%eax
--
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