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- From: pcolmer@acorn.co.uk (Philip Colmer)
- Subject: Useful hints and tips #1: !Run files
- Date: 14 Jun 93 15:17:23 GMT
-
- 1. Loading modules from !System
- -------------------------------
-
- Often, applications that may or may not need to load modules from !System
- simply check System$Path before seeing whether or not anything does need to
- be loaded from !System. This is particularly annoying with RISC OS 3 since
- there currently shouldn't be any need for OS-originated modules.
-
- A way around this problem would be to use something along the lines of:
-
- RMEnsure UtilityModule 3.00 If "<System$Path>" = "" Then Error 0 System
- resources cannot be found
-
- Set System$Path_Message System resources cannot be found
-
- The first line basically states that if the machine hasn't got RISC OS
- 3.00 orlater, and System$Path isn't set, then complain. This would be the
- default action under RISC OS 2, so nothing has changed there.
-
- The second line uses a new feature of RISC OS 3. Basically what the line
- is saying is that if there is an access to System: and System$Path isn't
- defined, give the error 'System resources cannot be found'.
-
- 2. Duplication of !Boot
- -----------------------
-
- If you look at a lot of applications, the !Run files fall into three categories:
-
- 1. They run !Boot at some point
- 2. They include the commands in !Boot
- 3. There is no common ground at all.
-
- The third is obviously flawed since the !Boot file may not have been
- executed. It is therefore necessary, in some way, to execute the commands
- that the !Boot file contains. The best way to do this is to COPY the
- commands from the !Boot file and put them into the !Run file.
-
- Doing it this way is more network-friendly that running the !Boot file
- form the !Run file.
-
- An associated point is that if the !Boot file just contains:
-
- IconSprites <Obey$Dir>.!Sprites
-
- then it is a waste of time and space. In the absence of a !Boot file, the
- Filer will do this anyway.
-
- 3. Careful setting of slot sizes
- --------------------------------
-
- When setting the slot size for your application, exercise some caution and
- try to test your application on a small-paged machine. This is important
- because the page size varies from 8K up to 32K depending on the amount of
- memory that your machine has.
-
- It is also worth remembering that the Window Manager rounds the requested
- slot size UP to the nearest page size, which holds hidden perils if you
- have specified a slot size too small for an 8K page size machine but which,
- when rounded up, works fine on a 32K page size machine.
-
- ---------------------------------------------------------------------
- "Now, I realise that, technically speaking, that's only one flaw, but
- I thought that it was such a big one, it was worth mentioning twice."
-
-
-