Cooperative Record Locking - Revision history

Costel Mincea: Text replacement - "" to ""

2025-01-26T19:30:20Z

Text replacement - "<syntaxhighlight>" to "<syntaxhighlight lang="C" line>"

← Older revision		Revision as of 19:30, 26 January 2025
Line 23:		Line 23:
	individual record locks:		individual record locks:

	<syntaxhighlight>		<syntaxhighlight lang="C" line>
	BOOL LockRecord(BPTR myFH, ULONG my_offset, ULONG my_length, ULONG my_mode, ULONG my_timeout);		BOOL LockRecord(BPTR myFH, ULONG my_offset, ULONG my_length, ULONG my_mode, ULONG my_timeout);
	BOOL UnLockRecord(BPTR myFH, ULONG my_offset, ULONG my_length);		BOOL UnLockRecord(BPTR myFH, ULONG my_offset, ULONG my_length);
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	DOS Library offers a function to lock an array of record locks:		DOS Library offers a function to lock an array of record locks:

	<syntaxhighlight>		<syntaxhighlight lang="C" line>
	BOOL LockRecords(struct RecordLock *recordarray, ULONG multi_timeout);		BOOL LockRecords(struct RecordLock *recordarray, ULONG multi_timeout);
	</syntaxhighlight>		</syntaxhighlight>
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	(as defined in <dos/record.h>):		(as defined in <dos/record.h>):

	<syntaxhighlight>		<syntaxhighlight lang="C" line>
	struct RecordLock {		struct RecordLock {
	BPTR rec_FH; /* The file handle of the data file */		BPTR rec_FH; /* The file handle of the data file */
Line 85:		Line 85:
	To unlock records locked by LockRecords(), use the dos.library function UnLockRecords():		To unlock records locked by LockRecords(), use the dos.library function UnLockRecords():

	<syntaxhighlight>		<syntaxhighlight lang="C" line>
	BOOL UnLockRecords(struct RecordLock *recordarray);		BOOL UnLockRecords(struct RecordLock *recordarray);
	</syntaxhighlight>		</syntaxhighlight>
Line 132:		Line 132:
	=== LockRecord.c ===		=== LockRecord.c ===

	<syntaxhighlight>		<syntaxhighlight lang="C" line>
	// LockRecord.c		// LockRecord.c
	//		//
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	=== ExRecLock1.c ===		=== ExRecLock1.c ===

	<syntaxhighlight>		<syntaxhighlight lang="C" line>
	// ExRecLock1.c		// ExRecLock1.c
	//		//
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	=== ExRecLock2.c ===		=== ExRecLock2.c ===

	<syntaxhighlight>		<syntaxhighlight lang="C" line>
	// ExRecLock2.c		// ExRecLock2.c
	//		//

Steven Solie: /* Locking Records Using DOS Packets */

2013-03-19T20:46:34Z

Locking Records Using DOS Packets

← Older revision		Revision as of 20:46, 19 March 2013
Line 98:		Line 98:
	{{Note\|title=Don't use DOS Packets\|text=DOS Library now handles record locking as of version 53.?? so that file systems are no longer burdened with implementing this functionality. The information below is being provided for reference and for users of previous versions of the DOS Library.}}		{{Note\|title=Don't use DOS Packets\|text=DOS Library now handles record locking as of version 53.?? so that file systems are no longer burdened with implementing this functionality. The information below is being provided for reference and for users of previous versions of the DOS Library.}}

	To lock a record using the DOS packet interface, send an ACTION_LOCK_RECORD (2008) packet to the file system. This packet		To lock a record using the DOS packet interface, send an ACTION_LOCK_RECORD (2008) packet to the file system. This packet uses the following arguments:
	uses the following arguments:

	<pre>		<pre>

Steven Solie at 19:53, 19 March 2013

2013-03-19T19:53:03Z

← Older revision		Revision as of 19:53, 19 March 2013
Line 6:		Line 6:
	the starting position of the record from the beginning of the file. The size and offset can vary from record to record. The only limit		the starting position of the record from the beginning of the file. The size and offset can vary from record to record. The only limit
	on a record's size and offset are the limits the file system has on the size of the file.		on a record's size and offset are the limits the file system has on the size of the file.

			== File System or DOS? ==

			Starting with version 53.x of the DOS Library (dos.library), the record locking feature is handled entirely by AmigaDOS. DOS record locking is independent of the file system and is always available. Prior to this version, record locking was available only if each individual file system implemented the feature. If a file system does not record locking, the record locking functions described below will always fail.

	== Record Lock Types ==		== Record Lock Types ==

Steven Solie: /* ExRecLock2.c */

2013-03-14T23:31:58Z

ExRecLock2.c

← Older revision		Revision as of 23:31, 14 March 2013
Line 608:		Line 608:
	// attempt will fail.		// attempt will fail.

	#include <~~clib~~/~~dos_protos~~.h>		#include <proto/dos.h>
	#include <clib/alib_protos.h>
	#include <clib/alib_stdio_protos.h>

	#define RECORDSIZE 12		#define RECORDSIZE 12
	#define RECORDOFFSET 12		#define RECORDOFFSET 12

	extern struct Library *DOSBase;

	UBYTE *vers = "\0$VER: ExRecLock2 37.2";
	UBYTE string = "ExRecLock2\n"; / This string will be the */		UBYTE string = "ExRecLock2\n"; / This string will be the */
	/* contents of the record. */		/* contents of the record. */
	~~void~~ main(~~void~~)		int main()
	{		{
	BPTR fh;		BPTR fh;

		⚫	if (fh = IDOS->Open("t:testRLock", MODE_READWRITE)) /* Open the file, creating */
	if (DOSBase->lib_Version >= 37) /* Record locking was introduced in Release 2, */
	{ /* ~~but~~ ~~the~~ ~~standard~~ ~~startup~~ ~~code~~ ~~will~~ ~~open~~ ~~any~~ */		{ /* it if necessary. */
	/* ~~version~~ of ~~dos.library, so we have to ex-~~ */		if (DOSTRUE == IDOS->LockRecord(fh, /* Lock the record as exclusive, */
	/* ~~plicitly~~ ~~check~~ ~~the~~ ~~version~~ ~~number~~ of ~~DOS.~~ */		RECORDOFFSET, /* and do not wait if it is not */
		⚫	RECORDSIZE, /* available immediately. */

		⚫	REC_EXCLUSIVE_IMMED, 0))
⚫	if (fh = Open("t:testRLock", MODE_READWRITE)) /* Open the file, creating */
		⚫	{
	{ /* it if necessary. */
		⚫	LONG error = RECORDOFFSET;
	if (DOSTRUE == LockRecord(fh, /* Lock the record as exclusive, */
	RECORDOFFSET, /* and do not wait if it is not */
⚫	RECORDSIZE, /* available immediately. */
⚫	REC_EXCLUSIVE_IMMED, 0))
⚫	{
⚫	LONG error = RECORDOFFSET;

	/* If the record is beyond the end of the file, */		/* If the record is beyond the end of the file, */
	if (Seek(fh, 0, OFFSET_END) < RECORDOFFSET) /* lengthen the file. */		if (IDOS->Seek(fh, 0, OFFSET_END) < RECORDOFFSET) /* lengthen the file. */
	error = SetFileSize(fh, RECORDOFFSET, OFFSET_BEGINNING);		error = IDOS->SetFileSize(fh, RECORDOFFSET, OFFSET_BEGINNING);

	if (error == RECORDOFFSET) /* If there was no error with the file */		if (error == RECORDOFFSET) /* If there was no error with the file */
	{ /* file size, continue. */		{ /* file size, continue. */
	if (Seek(fh, RECORDOFFSET, OFFSET_BEGINNING) < 0)		if (IDOS->Seek(fh, RECORDOFFSET, OFFSET_BEGINNING) < 0)
	PrintFault(IoErr(), "Seek() error");		IDOS->PrintFault(IDOS->IoErr(), "Seek() error");

	if (Write(fh, string, RECORDSIZE) < 0)		if (IDOS->Write(fh, string, RECORDSIZE) < 0)
	PrintFault(IoErr(), "Write() error");		IDOS->PrintFault(IDOS->IoErr(), "Write() error");
	else		else
	PutStr("Write successful, ");		IDOS->PutStr("Write successful, ");
	}
	PutStr("Waiting 10 seconds...\n");
	TimeDelay(UNIT_VBLANK, 10, 0); /* Amiga.lib function that puts */
	/* a task to sleep for a given amount of time. This waits */
	/* 10 seconds before unlocking the record to give the user */
	/* a chance to start a second copy of this example. */
⚫	UnLockRecord(fh, RECORDOFFSET, RECORDSIZE);
	}		}
	~~else PrintFault~~(~~IoErr(),~~ "~~Record~~ ~~Lock~~ ~~Failed~~");		IDOS->PutStr("Waiting 10 seconds...\n");
	~~Close~~(fh);		IDOS->Delay(10 * 50);
		⚫	IDOS->UnLockRecord(fh, RECORDOFFSET, RECORDSIZE);
	}		}
	else PrintFault(IoErr(), "~~Open~~ Failed");		else IDOS->PrintFault(IDOS->IoErr(), "Record Lock Failed");
			IDOS->Close(fh);
	}		}
			else IDOS->PrintFault(IDOS->IoErr(), "Open Failed");
	else PutStr("Need dos.library V37 or greater.\n");
	}		}
	</syntaxhighlight>		</syntaxhighlight>

Steven Solie: /* ExRecLock1.c */

2013-03-14T23:29:27Z

ExRecLock1.c

← Older revision		Revision as of 23:29, 14 March 2013
Line 551:		Line 551:
	// attempt will fail.		// attempt will fail.

	#include <~~clib~~/~~dos_protos~~.h>		#include <protob/dos.h>
	#include <clib/alib_protos.h>
	#include <clib/alib_stdio_protos.h>

	#define RECORDSIZE 12		#define RECORDSIZE 12
	#define RECORDOFFSET 0		#define RECORDOFFSET 0

	extern struct Library *DOSBase;

	UBYTE *vers = "\0$VER: ExRecLock1 37.2";
	UBYTE string = "ExRecLock1\n"; / This string will be the */		UBYTE string = "ExRecLock1\n"; / This string will be the */
	/* contents of the record. */		/* contents of the record. */
	~~void~~ main(~~void~~)		int main()
	{		{
	BPTR fh;		BPTR fh;

		⚫	if (fh = IDOS->Open("t:testRLock", MODE_READWRITE)) /* Open the file, creating */
	if (DOSBase->lib_Version >= 37) /* Record locking was introduced in Release 2, */
	{ /* ~~but~~ ~~the~~ ~~standard~~ ~~startup~~ ~~code~~ ~~will~~ ~~open~~ ~~any~~ */		{ /* it if necessary. */
	/* ~~version~~ of ~~dos.library, so we have to ex-~~ */		if (DOSTRUE == IDOS->LockRecord(fh, /* Lock the record as exclusive, */
	/* ~~plicitly~~ ~~check~~ ~~the~~ ~~version~~ ~~number~~ of ~~DOS.~~ */		RECORDOFFSET, /* and do not wait if it is not */
		⚫	RECORDSIZE, /* available immediately. */

		⚫	REC_EXCLUSIVE_IMMED, 0))
⚫	if (fh = Open("t:testRLock", MODE_READWRITE)) /* Open the file, creating */
		⚫	{
	{ /* it if necessary. */
		⚫	LONG error = RECORDOFFSET;
	if (DOSTRUE == LockRecord(fh, /* Lock the record as exclusive, */
	RECORDOFFSET, /* and do not wait if it is not */
⚫	RECORDSIZE, /* available immediately. */
⚫	REC_EXCLUSIVE_IMMED, 0))
⚫	{
⚫	LONG error = RECORDOFFSET;

	/* If the record is beyond the end of the file, */		/* If the record is beyond the end of the file, */
	if (Seek(fh, 0, OFFSET_END) < RECORDOFFSET) /* lengthen the file. */		if (IDOS->Seek(fh, 0, OFFSET_END) < RECORDOFFSET) /* lengthen the file. */
	error = SetFileSize(fh, RECORDOFFSET, OFFSET_BEGINNING);		error = IDOS->SetFileSize(fh, RECORDOFFSET, OFFSET_BEGINNING);

	if (error == RECORDOFFSET) /* If there was no error with the file */		if (error == RECORDOFFSET) /* If there was no error with the file */
	{ /* file size, continue. */		{ /* file size, continue. */
	if (Seek(fh, RECORDOFFSET, OFFSET_BEGINNING) < 0)		if (IDOS->Seek(fh, RECORDOFFSET, OFFSET_BEGINNING) < 0)
	PrintFault(IoErr(), "Seek() error");		IDOS->PrintFault(IDOS->IoErr(), "Seek() error");

	if (Write(fh, string, RECORDSIZE) < 0)		if (IDOS->Write(fh, string, RECORDSIZE) < 0)
	PrintFault(IoErr(), "Write() error");		IDOS->PrintFault(IDOS->IoErr(), "Write() error");
	else		else
	PutStr("Write successful, ");		IDOS->PutStr("Write successful, ");
	}
	PutStr("Waiting 10 seconds...\n");
	TimeDelay(UNIT_VBLANK, 10, 0); /* Amiga.lib function that puts */
	/* a task to sleep for a given amount of time. This waits */
	/* 10 seconds before unlocking the record to give the user */
	/* a chance to start a second copy of this example. */
⚫	UnLockRecord(fh, RECORDOFFSET, RECORDSIZE);
	}		}
	~~else PrintFault~~(~~IoErr(),~~ "~~Record~~ ~~Lock~~ ~~Failed~~");		IDOS->PutStr("Waiting 10 seconds...\n");
	~~Close~~(fh);		IDOS->Delay(10 * 50);
		⚫	IDOS->UnLockRecord(fh, RECORDOFFSET, RECORDSIZE);
	}		}
	else PrintFault(IoErr(), "~~Open~~ Failed");		else IDOS->PrintFault(IDOS->IoErr(), "Record Lock Failed");
			IDOS->Close(fh);
	}		}
			else IDOS->PrintFault(IDOS->IoErr(), "Open Failed");
	else PutStr("Need dos.library V37 or greater.\n");
	}		}
	</syntaxhighlight>		</syntaxhighlight>

Steven Solie: /* LockRecord.c */

2013-03-14T23:25:42Z

LockRecord.c

Show changes

Steven Solie: /* LockRecord.c */

2013-03-14T22:14:55Z

LockRecord.c

@@ Line 130: / Line 130: @@
 <syntaxhighlight>
-; /* LockRecord.c - Execute me to compile me with SAS/C 6.56
+// LockRecord.c
-slink FROM LockRecord.o to LockRecord LIB lib:amiga.lib
+// LockRecord()/UnLockRecord() example.
 #include <exec/memory.h>

Steven Solie: /* ExRecLock1.c */

2013-03-14T22:14:02Z

ExRecLock1.c

@@ Line 577: / Line 577: @@
 <syntaxhighlight>
-;/* ExRecLock1.c - Execute me to compile me with SAS/C 6.56
+// ExRecLock1.c
 #include <clib/dos_protos.h>
 #include <clib/alib_protos.h>
 #include <clib/alib_stdio_protos.h>
 #define RECORDSIZE   12

Steven Solie: /* ExRecLock1.c */

2013-03-14T22:12:51Z

ExRecLock1.c

@@ Line 662: / Line 662: @@
 </syntaxhighlight>
-=== ExRecLock1.c ===
+=== ExRecLock2.c ===
 <syntaxhighlight>
-;/* ExRecLock2.c - Execute me to compile me with SAS/C 6.56
+// ExRecLock2.c
 #include <clib/dos_protos.h>
 #include <clib/alib_protos.h>
 #include <clib/alib_stdio_protos.h>
 #define RECORDSIZE   12

Steven Solie: /* Examples */

2013-03-14T22:11:33Z

Examples

Show changes