A fast and easily customised operating system
for ARM devices
OS_File 24
Programmer's Reference Manuals
» Part 15 – SWI Calls
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OS_ File 24
(SWI &08)
| Entry | |
|---|---|
| R0 | 24 (reason code) |
| R1 | Pointer to filename |
| Exit | |
|---|---|
| R0 | Preserved |
| R1 | Preserved |
| R2 | Natural block size in bytes |
Use
The purpose of this call is to find the natural block size of a given file.
Notes
When you create or extend a file, disc space can only be allocated in chunks of a minimum size (512 bytes, for example). If your file is just 1 byte long for example, 511 bytes of disc space may have to be wasted after it if the natural block size is 512.