2

I'm interested by editing/erasing/copying/etc... code lines in *.prc file ( executable for Palm OS ). I tried to open prc files with text editors ( notepad and others ) but I cannot see code just symbols... So, I don't know... what I want to do is... possible? If it is, how can I do it? With an IDE? Without?

I would like to notify that I'm a beginner in programming, I looked for an answer to my question but I have not found, maybe because it's a too simple question. If it is, I'm very sorry!

Thank you!

Matt Sephton
  • 3,711
  • 4
  • 35
  • 46
Kelthaas
  • 21
  • 1

2 Answers2

1

PalmOS .prc files lend themselves very well to editing.

They're actually a database with tables of many types of resources, including but not limited to: bitmaps, preferences, strong, form definitions, alert definitions, icons, version numbers and executable code.

screen grab from PRC Explorer

It's a little like the resource fork approach seen on Classic Macintosh files.

Anyway, depending on what you want to edit you'll have to approach things differently.

Apps to check out are:

  • Bird (PalmOS) to change forms, strings, version numbers, etc.
    • I've used this to correct typos, fix form layout bugs, translate apps

Yes! You can edit an app right there on the device.

On Windows:

  • PRCExplorer for browsing the .prc contents
    • I've used this to export graphics
  • PRCEdit for decompiling and patching the .prc
    • I've used this to hack/patch logic checks
  • PRC Tools (also modern version for Mac & Linux)
  • palmdeMON (pdemon.zip)

Download the above four here

  • PilRC - use this to rebuild a .prc from component parts

  • Presdec (not tried this myself)

  • PFCD (The Palm File Compiler / Decompiler) (not tried this myself)

A bunch more here: https://www.massena.com/darrin/pilot/tanda.htm

An example of doing something with these tools: https://lesliefranke.com/2006/04/updating-zlauncher-themes/

Obviously the majority of this stuff is 15+ years since abandoned. But, there's an active Palm-focused Discord where you can talk to other PalmOS users: https://discord.gg/YddKPpR

Matt Sephton
  • 3,711
  • 4
  • 35
  • 46
0

There are no "code lines" in a PRC file. It is a binary executable, a product of compilation; you would need to either obtain a source code (which you could then edit and compile to make a new PRC), or you can use a debugger to inspect it as-is (which requires a very high level of skill).

See here for more details. In general, you'd need to learn C first. I would highly suggest you start learning programming on another target, since you will not find as abundant resources for PalmOS as you will for Windows, OSX, Linux, iOS or Android. When you are fluent in C, you can attempt to figure out how to use it for PalmOS.

Amadan
  • 191,408
  • 23
  • 240
  • 301
  • Your answer is correct at a high level, but fails to mention the unique aspect of Palm .prc files - namely that they can be easily edited without touching the code. The code of course can be decompiled, even on the device itself! I hope you find my answer above somewhat enlightening. – Matt Sephton Nov 06 '19 at 02:01
  • @MattSephton: You are right, of course — except OP wanted to edit "code lines". I am not sure how one would edit "code lines" but "without touching the code". (I haven't ever used a PRC decompiler, so no idea how legible decompiled code is...) – Amadan Nov 06 '19 at 02:07
  • 1
    I think the real purpose of the OP is lost in translation. Maybe one day we'll find out!? – Matt Sephton Nov 06 '19 at 02:20