mirror of
https://github.com/alfishe/amiga-bootcamp.git
synced 2026-06-12 16:16:28 +00:00
21751c0025
Comprehensive technical documentation covering: - Hardware: OCS/ECS/AGA custom chip registers, Copper & Blitter deep dives - Boot sequence: cold boot through startup-sequence - Binary format: HUNK executable spec, relocation, debug info - Linking & ABI: .fd files, LVO tables, register calling conventions - Exec kernel: tasks, interrupts, memory, signals, semaphores - AmigaDOS: file I/O, FFS/OFS layout, CLI/Shell scripting - Graphics: planar bitmaps, Copper programming, HAM/EHB modes - Intuition: screens, windows, IDCMP, BOOPSI - Devices: trackdisk, SCSI, serial, timer, audio, keyboard - Libraries: utility, expansion, IFFParse, locale, ARexx - Networking: bsdsocket API, SANA-II, TCP/IP stack comparison - Toolchain: GCC, vasm/vlink, SAS/C, NDK, debugging - Reverse engineering: IDA/Ghidra setup, compiler fingerprints, case studies - CPU & MMU: 68040/060 emulation libs, PMMU, cache management - Driver development: SANA-II, Picasso96/RTG, AHI audio All files include breadcrumb navigation. No local paths or proprietary content.
67 lines
1.8 KiB
Markdown
67 lines
1.8 KiB
Markdown
[← Home](../README.md) · [AmigaDOS](README.md)
|
||
|
||
# Environment Variables — GetVar, SetVar
|
||
|
||
## Overview
|
||
|
||
AmigaDOS supports both **local** (per-process) and **global** (system-wide) environment variables. Local variables are stored in the process's `pr_LocalVars` MinList; global variables are stored as files in `ENV:` (RAM-backed) and `ENVARC:` (persistent on disk).
|
||
|
||
---
|
||
|
||
## API
|
||
|
||
| LVO | Function | Description |
|
||
|---|---|---|
|
||
| −900 | `GetVar(name, buf, size, flags)` | Read a variable |
|
||
| −906 | `SetVar(name, buf, size, flags)` | Set or create a variable |
|
||
| −912 | `DeleteVar(name, flags)` | Remove a variable |
|
||
| −918 | `FindVar(name, type)` | Find a LocalVar node |
|
||
|
||
### Flags
|
||
|
||
```c
|
||
/* dos/var.h — NDK39 */
|
||
#define GVF_GLOBAL_ONLY 0x100 /* search only ENV: */
|
||
#define GVF_LOCAL_ONLY 0x200 /* search only pr_LocalVars */
|
||
#define GVF_BINARY_VAR 0x10 /* treat value as binary data */
|
||
#define GVF_DONT_NULL_TERM 0x20 /* don't null-terminate result */
|
||
#define LV_VAR 0 /* standard variable */
|
||
#define LV_ALIAS 1 /* shell alias */
|
||
```
|
||
|
||
---
|
||
|
||
## Usage
|
||
|
||
```c
|
||
/* Set a global variable: */
|
||
SetVar("EDITOR", "ed", -1, GVF_GLOBAL_ONLY);
|
||
|
||
/* Read it back: */
|
||
char buf[256];
|
||
if (GetVar("EDITOR", buf, sizeof(buf), 0) >= 0) {
|
||
Printf("EDITOR = %s\n", buf);
|
||
}
|
||
|
||
/* Delete: */
|
||
DeleteVar("EDITOR", GVF_GLOBAL_ONLY);
|
||
```
|
||
|
||
---
|
||
|
||
## Storage Locations
|
||
|
||
| Scope | Storage | Persistent? |
|
||
|---|---|---|
|
||
| Local | `pr_LocalVars` MinList (in-memory) | No — dies with process |
|
||
| Global (volatile) | `ENV:` — assign to `RAM:Env/` | No — lost on reboot |
|
||
| Global (persistent) | `ENVARC:` — assign to `SYS:Prefs/Env-Archive/` | Yes — survives reboot |
|
||
|
||
The startup-sequence copies `ENVARC:` to `ENV:` at boot.
|
||
|
||
---
|
||
|
||
## References
|
||
|
||
- NDK39: `dos/var.h`
|
||
- ADCD 2.1: `GetVar`, `SetVar`, `DeleteVar`
|