Lazarus
Home
Help
TinyPortal
Search
Login
Register
Lazarus
»
Forum
»
Programming
»
General
»
questions concerning procedural types
Free Pascal
Website
Downloads
Wiki
Documentation
Bugtracker
Mailing List
Lazarus
Website
Downloads (Laz+FPC)
Packages (OPM)
FAQ
Wiki
Documentation (RTL/FCL/LCL)
Bugtracker
CCR Bugs
IRC channel
GIT
Mailing List
Other languages
Foundation
Website
Useful Wiki Links
Project Roadmap
Getting the Source
Screenshots
How to use the forum
About donations (wiki)
Bookstore
Computer Math and Games in Pascal
(preview)
Lazarus Handbook
Search
Advanced search
Recent
May be useful to somebody
by
Handoko
[
Today
at 07:35:48 am]
How can I draw a rectangl...
by
Handoko
[
Today
at 07:30:55 am]
Draw a line in the Scroll...
by
Handoko
[
Today
at 07:27:54 am]
Offical launch of the 1 B...
by
Handoko
[
Today
at 06:05:11 am]
Debugger crashes with App...
by
trev
[
Today
at 06:00:08 am]
Copyrights Q
by
domasz
[
Today
at 04:56:59 am]
web development using pas...
by
Nate897
[
Today
at 02:04:05 am]
questionable function def...
by
440bx
[
Today
at 01:35:28 am]
Why isn't TTIRadioGroup's...
by
jamie
[
Today
at 12:13:45 am]
Generics - correct syntax
by
jamie
[
Today
at 12:11:50 am]
Same project and two Pcs
by
caiov1n1c1us
[
Today
at 12:04:00 am]
v3.99 code completion que...
by
440bx
[April 22, 2024, 11:08:26 pm]
add new targets to make
by
marcov
[April 22, 2024, 09:32:20 pm]
[SOLVED]RichMemo StringRe...
by
KodeZwerg
[April 22, 2024, 08:44:40 pm]
[SOLVED] LAMW/Linux - Ins...
by
Alcatiz
[April 22, 2024, 08:04:06 pm]
[SOLVED] TimeStampToMSecs...
by
korba812
[April 22, 2024, 06:23:33 pm]
Quirky windows
by
ASerge
[April 22, 2024, 06:23:20 pm]
Access violation when re-...
by
cdbc
[April 22, 2024, 05:39:59 pm]
trunk compiler bug for mi...
by
nickysn
[April 22, 2024, 04:05:11 pm]
FPDebug: Evaluate/Modify ...
by
bpranoto
[April 22, 2024, 03:14:12 pm]
Your best UI design - con...
by
lainz
[April 22, 2024, 02:28:00 pm]
Access violation when ope...
by
Чебурашка
[April 22, 2024, 02:07:58 pm]
Unlocking Files
by
KodeZwerg
[April 22, 2024, 12:39:53 pm]
[SOLVED] what is function...
by
Martin_fr
[April 22, 2024, 12:14:59 pm]
[SOLVED] how to build the...
by
Laksen
[April 22, 2024, 10:45:18 am]
« previous
next »
Print
Pages: [
1
]
Author
Topic: questions concerning procedural types (Read 603 times)
anonymousstranger
New Member
Posts: 49
questions concerning procedural types
«
on:
January 17, 2021, 02:54:42 am »
1) Given:
Code: Pascal
[Select]
[+]
[-]
Type
TOneArgCcall
=
Procedure
(
Var
X
:
integer
)
;
var
proc
:
TOneArgCcall
;
Procedure
printit
(
Var
X
:
Integer
)
;
begin
WriteLn
(
x
)
;
end
;
begin
Proc
:
=
@
printit
;
end
.
How does one pass a value into printit through proc? I'm kind of fuzzy on how this works.
2)Say you have a procedural type that references a procedure/function in a library. does the procedural type also require the "external" tag?
«
Last Edit: January 17, 2021, 03:05:41 am by anonymousstranger
»
Logged
Blaazen
Hero Member
Posts: 3241
POKE 54296,15
Re: questions concerning procedural types
«
Reply #1 on:
January 17, 2021, 03:22:35 am »
Since you pass variable x by reference (
var
), you have to write:
Code: Pascal
[Select]
[+]
[-]
var
i
:
Integer
;
begin
Proc
:
=
@
printit
;
i
:
=
5
;
Proc
(
i
)
;
end
;
i
can be global variable as well.
Don't know about external keyword.
Logged
Lazarus 2.3.0 (rev main-2_3-2863...) FPC 3.3.1 x86_64-linux-qt Chakra, Qt 4.8.7/5.13.2, Plasma 5.17.3
Lazarus 1.8.2 r57369 FPC 3.0.4 i386-win32-win32/win64 Wine 3.21
Try Eye-Candy Controls:
https://sourceforge.net/projects/eccontrols/files/
anonymousstranger
New Member
Posts: 49
Re: questions concerning procedural types
«
Reply #2 on:
January 17, 2021, 05:09:13 am »
cool
thanks.
Logged
Print
Pages: [
1
]
« previous
next »
Lazarus
»
Forum
»
Programming
»
General
»
questions concerning procedural types
TinyPortal
© 2005-2018