TweetFollow Us on Twitter

Easy FKEY
Volume Number:8
Issue Number:2
Column Tag:Pascal Workshop

Related Info: File Manager Event Manager

FKEYs in THINK Pascal, Easy

Have you ever had to restart because a file was left open? No more! Read on.

By Roy Lovejoy, Sunnyvale, California

Note: Source code files accompanying article are located on MacTech CD-ROM or source code disks.

About the author

Roy Lovejoy is a Software Engineer at Calera Recognition Systems. He was previously working at Claris Corporation as one of the MacWrite II engineers. This is his first article for MacTutor. What do you think?

A Bit of History

When the Macintosh arrived on the scene in February of 1984, the world knew it was unique; its profile, screen, and keyboard were all different from the then-standard IBM PC. One of the attributes that IBM-ers scoffed at was the lack of "Function keys". You know function keys, those funky little buttons that do an infinitely many different things (depending on which program you are running). Well, we have news for the scoffers. The Macintosh has had function keys, or FKEY’s as they are called, since its inception.

The FKEY’s that were included were ones to eject the internal and external floppy disk, take a snapshot of the screen and save it to a MacPaint file, and print the screen, or the front window. These FKEY’s were assigned numbers 1 , 2, 3, and 4 respectively and were triggered by the Command key followed by the associated digit. Since the introduction of different size and depth screens, and printers, they of course had to be modified. Many people have written other useful FKEY's, and some have become very well known (i.e., switch-a-roo).

FKEY's are a pretty safe bet. Since they are trapped during a GetNextEvent or WaitNextEvent, they are available in a large percentage of applications. Since Desk Accessories are going the way of the brontosaurus, or so they say, FKEY’s are (hopefully) a safe utility feature in the future.

General

Now these function keys are in no way difficult to code. They are just simply different to code. I have found that if I need a utility, an FKEY is always my first choice, then comes a Desk Accessory, then an Application. (You don’t have all of the DRVR problems that are inherent in a desk accessory.) Basically an FKEY is a procedure that has no true globals (true globals are ones that are referenced off of the 68000 register A5) and is compiled to an 'FKEY' resource. There are many safe, and many sneaky ways to have a 'global' area, but that will be good subject matter for a future article.

An FKEY can be completely Modal - it might simply bring up a Dialog and let you set/reset a value, or it can have a robust user interface, complete with menus and windows. This article will describe the former.

In THINK Pascal, an FKEY is simply a unit that is compiled into a resource, of type FKEY. See figure for Project Setup. The unit must have the entry procedure be called ‘main’ and have no parameters. There must not be a ‘program’. See Figure 1.

Figure 1: Set Project Dialog (set for FKEY #5)

Why did I write this?

As an applications programmer I have many times (read > 300) written file I/O routines that save and retrieve program’s data structures. Naturally, in the course of human events, errors happen, sunspots appear, neutrinos expire, all after you open a data file, but before you get a chance to close it properly. This problem leads to a file, on your storage device, that is marked busy. This file can not be closed by your program (your variables have since committed electronic suicide, and your FileRefNum has gone with them), and you can not throw the file out, (because the busy bit is set). So, what do you do? Well, the busy bit is reset when the volume gets dismounted. That is acceptable for a floppy disk, but if it is your currently-booted hard disk, that poses a problem. What I wanted to do was an FSClose on the file, regardless of how it got opened. I was very frustrated, logged countless hours on networks looking for a utility to ease my woes. Finally I said, forget it, I’ll do it myself. Here it is.

What does it do?

Basically, when you (or any application) do an FSOpen or equivalent, memory is allocated for the file’s information. This FKEY simply tries to open the file; if the file is already open, it makes a parameter block call to get the file reference number, then uses that to close the file. If the file was not open originally, it is now because of the FSOpen, and so the FKEY goes ahead and closes it. A diagnostic dialog makes everything friendly.

A Bit of Style

The final resting place of an FKEY is either the System File or an exterior resource opened by a Suitcase-like program. This does not mean you can’t debug it elegantly. Oh, sure. “It’s a code resource. Those are hard to debug!!” I have some Arizona beach front property for you, too. What I do is have two Think projects. One has the standard Runtime.Lib and an extra file that is just a program stub that calls ‘Main’. I can then go on and debug in the glorious THINK environment. The other project has the DRVRruntime.lib and no ‘program’ file. This one has debugging turned off and the project type set to code resource. See Figures 2 and 3.

Figure 2: Project Set Up for debugging

Figure 3: Project Set Up for compiling

Listing

{======================}
unit FKEY;
{======================}
interface
{======================}
 procedure Main;
{======================}
implementation
{======================}
 procedure Main;
 var
 dlgOrigin: Point; {Top-left corner of dialog box}
 theReply: SFReply;{Data returned by SFGet dialog}
 theFile: INTEGER; {Reference number of file}
 resultCode: OSErr;{I/O error code}
 TypeList: SFTypeList;  {Type List to search for }
 Block: ParamBlockRec;  {Used to get file ref number}
 WIND: WindowPtr;{Display Window }
 bounds: Rect; {window rectangle Rectangle }
 OldPort: GrafPtr; {Graf Port set upon entry}
 dummy: LONGINT; {parameter of Delay}
{======================}
{ CenterDraw}
{ Input: String to Draw , line number to draw on.}
{ (String is centered horizontally on the window.)}
{======================}
 procedure CenterDraw (s: Str255; y: INTEGER);
 var
 x: INTEGER;
 begin
 with WIND^.portRect do
 begin
 x := (right + left) div 2 - StringWidth(s) div 2;
 MoveTo(x, y * 16);
 end;
 DrawString(s);
 end;
{======================}
 begin
 GetPort(OldPort);
 SetRect(bounds, 85, 40, 420, 100);
 WIND := NewWindow(nil, bounds, '', TRUE, dBoxProc, pointer(-1), FALSE, 
0);
 SetPort(WIND);
 TextFace([underline]);
 CenterDraw('Close File FKEY', 1);
 TextFace([]);
 CenterDraw('Select the file you wish to close.', 2);

 SetPt(dlgOrigin, 85, 120);         {Set up dialog origin}
 SFGetFile(dlgOrigin, '', nil, -1, TypeList, nil, TheReply);

 with TheReply do
 if good then
 begin
{Try to open file}
 resultCode := FSOpen(fname, vRefNum, theFile);
{if it was already open, get the file ref number}
 if resultCode = opWrErr then
 with Block do
 begin
 ioNamePtr := @fName;
 ioVRefNum := vRefNum;
 ioFDirIndex := -1;
 resultCode := PBGetFInfo(@Block, false);  {Get Finder info}
 theFile := ioFRefNum;
 CenterDraw(Concat('“', fName, '” is now closed.'), 3);
 end
 else
 CenterDraw(Concat('“', fName, '” was not open.'), 3);
{Do the actual closing... regardless if it was open before the FKEY or 
not}
 ResultCode := fsClose(theFile);
 end;
 Delay(45, dummy);{Wait a while 3/4 of second}

 DisposeWindow(WIND); {Close up}
 SetPort(OldPort);
 end;
{======================}
end.
{======================}

program Test;
 uses
 FKEY;
begin
 Main;
end.

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

Airmail 3.3.2 - Powerful, minimal email...
Airmail is an mail client with fast performance and intuitive interaction. Support for iCloud, MS Exchange, Gmail, Google Apps, IMAP, POP3, Yahoo!, AOL, Outlook.com, Live.com. Airmail was designed... Read more
Numi 3.15.1 - Menu-bar calculator suppor...
Numi is a calculator that magically combines calculations with text, and allows you to freely share your computations. Numi combines text editor and calculator Support plain English. For example, '5... Read more
Airmail 3.3.2 - Powerful, minimal email...
Airmail is an mail client with fast performance and intuitive interaction. Support for iCloud, MS Exchange, Gmail, Google Apps, IMAP, POP3, Yahoo!, AOL, Outlook.com, Live.com. Airmail was designed... Read more
Numi 3.15.1 - Menu-bar calculator suppor...
Numi is a calculator that magically combines calculations with text, and allows you to freely share your computations. Numi combines text editor and calculator Support plain English. For example, '5... Read more
TextSoap 8.4.1 - Automate tedious text d...
TextSoap can automatically remove unwanted characters, fix up messed up carriage returns, and do pretty much anything else that we can think of to text. Save time and effort. Be more productive. Stop... Read more
TextSoap 8.4.1 - Automate tedious text d...
TextSoap can automatically remove unwanted characters, fix up messed up carriage returns, and do pretty much anything else that we can think of to text. Save time and effort. Be more productive. Stop... Read more
Backblaze 4.3.0.44 - Online backup servi...
Backblaze is an online backup service designed from the ground-up for the Mac. With unlimited storage available for $5 per month, as well as a free 15-day trial, peace of mind is within reach with... Read more
Numi 3.15 - Menu-bar calculator supports...
Numi is a calculator that magically combines calculations with text, and allows you to freely share your computations. Numi combines text editor and calculator Support plain English. For example, '5... Read more
EtreCheck 3.3.3 - For troubleshooting yo...
EtreCheck is an app that displays the important details of your system configuration and allow you to copy that information to the Clipboard. It is meant to be used with Apple Support Communities to... Read more
BusyContacts 1.1.8 - Fast, efficient con...
BusyContacts is a contact manager for OS X that makes creating, finding, and managing contacts faster and more efficient. It brings to contact management the same power, flexibility, and sharing... Read more

Latest Forum Discussions

See All

The best new games we played this week
We were quite busy this week. A bunch of big mobile games launched over the past few days, alongside a few teeny surprises. There're lots of quality games to load your phone with. We've gone and picked out five of our favorites for the week. [... | Read more »
Magikarp Jump beginner's guide
Magikarp Jump is a mystifying little game. Part Tamagotchi, part idle clicker, there's not a whole lot of video game there, per se, but for some reason we can't help coming back to it again and again. Your goal is to train up a little Magikarp to... | Read more »
Goat Simulator PAYDAY (Games)
Goat Simulator PAYDAY 1.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0 (iTunes) Description: ** IMPORTANT - SUPPORTED DEVICES **iPhone 4S, iPad 2, iPod Touch 5 or better Goat Simulator: Payday is the most... | Read more »
GRID Autosport delayed until autumn
Sorry mobile racing fans -- GRID Autosport has been delayed a few months. The game is now expected to launch this fall on iOS. Feral Interactive announced that they wanted more time to work on the game's UI and overall performance before launching... | Read more »
Zombie Gunship Survival Beginner's...
The much anticipated Zombie Gunship Survival is here. In this latest entry in the Zombie Gunship franchise, you're tasked with supporting ground troops and protecting your base from the zombie horde. There's a lot of rich base building fun, and... | Read more »
Mordheim: Warband Skirmish (Games)
Mordheim: Warband Skirmish 1.2.2 Device: iOS Universal Category: Games Price: $3.99, Version: 1.2.2 (iTunes) Description: Explore the ruins of the City of Mordheim, clash with other scavenging warbands and collect Wyrdstone -... | Read more »
Mordheim: Warband Skirmish brings tablet...
Legendary Games has just launched Mordheim: Warband Skirmish, a new turn-based action game for iOS and Android. | Read more »
Magikarp Jump splashes onto Android worl...
If you're tired ofPokémon GObut still want something to satisfy your mobilePokémon fix,Magikarp Jumpmay just do the trick. It's out now on Android devices the world over. While it looks like a simple arcade jumper, there's quite a bit more to it... | Read more »
Purrfectly charming open-world RPG Cat Q...
Cat Quest, an expansive open-world RPG from former Koei-Tecmo developers, got a new gameplay trailer today. The video showcases the combat and exploration features of this feline-themed RPG. Cat puns abound as you travel across a large map in a... | Read more »
Jaipur: A Card Game of Duels (Games)
Jaipur: A Card Game of Duels 1.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: ** WARNING: iPad 2, iPad Mini 1 & iPhone 4S are NOT compatible. ** *** Special Launch Price for a limited... | Read more »

Price Scanner via MacPrices.net

Memorial Day savings: 13-inch Touch Bar MacBo...
B&H Photo has the 2016 Apple 13″ Touch Bar MacBook Pros in stock today and on sale for up to $150 off MSRP. Shipping is free, and B&H charges NY & NJ sales tax only: - 13″ 2.9GHz/512GB... Read more
Apple refurbished 13-inch MacBook Airs availa...
Apple has Certified Refurbished 2016 13″ MacBook Airs available starting at $849. An Apple one-year warranty is included with each MacBook, and shipping is free: - 13″ 1.6GHz/8GB/128GB MacBook Air: $... Read more
Apple restocks refurbished 11-inch MacBook Ai...
Apple has Certified Refurbished 11″ MacBook Airs (the latest models recently discontinued by Apple), available for up to $170 off original MSRP. An Apple one-year warranty is included with each... Read more
12-inch 1.2GHz Retina MacBooks on sale for up...
B&H has 12″ 1.2GHz Retina MacBooks on sale for up to $150 off MSRP. Shipping is free, and B&H charges NY & NJ sales tax only: - 12″ 1.2GHz Space Gray Retina MacBook: $1449.99 $150 off... Read more
15-inch 2.7GHz Silver Touch Bar MacBook Pro o...
MacMall has the 15-inch 2.7GHz Silver Touch Bar MacBook Pro (MLW82LL/A) on sale for $2569 as part of their Memorial Day sale. Shipping is free. Their price is $230 off MSRP. Read more
Free Tread Wisely Mobile App Endorsed By Fath...
Just in time for the summer driving season, Cooper Tire & Rubber Company has announced the launch of a new Tread Wisely mobile app. Designed to promote tire and vehicle safety among teens and... Read more
Commercial Notebooks And Detachable Tablets W...
Worldwide shipments of personal computing devices (PCDs), comprised of traditional PCs (a combination of desktop, notebook, and workstations) and tablets (slates and detachables), are forecast to... Read more
Best value this Memorial Day weekend: Touch B...
Apple has Certified Refurbished 2016 15″ and 13″ MacBook Pros available for $230 to $420 off original MSRP. An Apple one-year warranty is included with each model, and shipping is free: - 15″ 2.6GHz... Read more
13-inch MacBook Airs on sale for up to $130 o...
Overstock.com has 13″ MacBook Airs on sale for up to $130 off MSRP including free shipping: - 13″ 1.6GHz/128GB MacBook Air (sku MMGF2LL/A): $869.99 $130 off MSRP - 13″ 1.6GHz/256GB MacBook Air (sku... Read more
2.8GHz Mac mini available for $973 with free...
Adorama has the 2.8GHz Mac mini available for $973, $16 off MSRP, including a free copy of Apple’s 3-Year AppleCare Protection Plan. Shipping is free, and Adorama charges sales tax in NY & NJ... Read more

Jobs Board

*Apple* Retail - Multiple Positions - Apple,...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
*Apple* Media Products - Commerce Engineerin...
Apple Media Products - Commerce Engineering Manager Job Number: 57037480 Santa Clara Valley, California, United States Posted: Apr. 18, 2017 Weekly Hours: 40.00 Job Read more
*Apple* Media Products - Commerce Engineerin...
Apple Media Products - Commerce Engineering Manager Job Number: 57037480 Santa Clara Valley, California, United States Posted: Apr. 18, 2017 Weekly Hours: 40.00 Job Read more
Best Buy *Apple* Computing Master - Best Bu...
**509643BR** **Job Title:** Best Buy Apple Computing Master **Location Number:** 001482- Apple Valley-Store **Job Description:** **What does a Best Buy Apple Read more
*Apple* Media Products - Commerce Engineerin...
Apple Media Products - Commerce Engineering Manager Job Number: 57037480 Santa Clara Valley, California, United States Posted: Apr. 18, 2017 Weekly Hours: 40.00 Job Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.