Palm Resource File Format

Introduction

This page describes the format of PRC (Palm resource) files used by the Palm OS.

PRC File Format

A PRC (Palm resource) file is very simple, starting immediately with the PRC header.

Type	Description	Notes
byte[32]	name	the name of the application, in MacRoman encoding, padded with nulls
int16be	attributes	Bit 0 (0x0001) is set, indicating this is a PRC file. Bit 1 (0x0002) indicates that the file is read-only. Bit 2 (0x0004) indicates that the appInfo field is dirty. Bit 3 (0x0008) indicates that the file needs to be backed up. Bit 4 (0x0010) indicates that it is OK to install a newer version of this file over an older one. Bit 5 (0x0020) indicates that the device should be reset after installing this application. Bit 6 (0x0040) indicates that the file cannot be copied to another device. Bit 7 (0x0080) is clear, indicating this is not a file stream database. Bit 8 (0x0100) indicates this file is hidden. Bit 9 (0x0200) is set, indicating this file is launchable. Bit 15 (0x8000) indicates the file is open and should be cleared. Other bits are reserved and should be cleared.
int16be	version	usually 1
int32be	creationDate	seconds since midnight, January 1, 1904
int32be	modificationDate	seconds since midnight, January 1, 1904
int32be	backupDate	seconds since midnight, January 1, 1904
int32be	modificationNumber	usually 0
int32be	appInfoOffset	offset from start of file to start of appInfo field; usually 0
int32be	sortInfoOffset	offset from start of file to start of sortInfo field; usually 0
int32be	type	for a PRC file, the four-character constant (fcc) appl
int32be	creator	a four-character constant (fcc) unique to this application
int32be	uniqueIDSeed	usually 0

Immediately following the header is an array of record lists. Usually there is only one record list, containing an array of resource records (or 4 zero bytes if there are no resources).

Type	Description	Notes
recordList[]	recordLists	an array of record lists
int32be	nextRecordListOffset	offset from this record list to the next record list; usually zero, indicating no further record lists
int16be	resourceCount	the number of resources
resource[]	resources	an array of resource records; 4 zero bytes if there are no resources
int32be	type	the resource type, a four-character constant (fcc)
int16be	id	the resource id
int32be	dataOffset	offset from start of file to start of resource data; end of resource data is indicated by next record or end of file

Following the record lists is the appInfo, which is usually empty; the sortInfo, which is usually empty; and finally the resource data.