Category:File Handling - Revision history

Saturn: slightly better hopefully?

2005-12-22T23:58:17Z

slightly better hopefully?

← Older revision		Revision as of 23:58, 22 December 2005
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	== General Explanation ==		== General Explanation ==
	~~Using~~ the commands and identifiers in this category ~~allows~~ you to ~~modify a file directly. That means that mIRC opens a connection to the specified and locks this connection when you are opening~~ a file ~~using [[Fopen\|/fopen]]. At the same moment~~, a (~~file-)pointer is set to the start of the file. You can now~~ read the character the pointer points to (either by using [[$fread]] that reads the entire line until the next [[$crlf]] or by using [[$fgetc]] that reads the "next" character only - note that the pointer is automatically moved to the begin of the next line / ~~next character by using these identifiers~~) ~~or move the pointer to another position in the file (by using [[Fseek\|/fseek]]). After you've modified you file~~, ~~you '''have to'''~~ close it ~~again (to unlock it and so make it accessible by other applications) using [[Fclose\|/fclose]]~~.		In addition to several high-level file access methods, mIRC offers a low-level way of accessing files, which closely resembles the way that operating systems like Windows or UNIX allow programs to access files. The individual commands and identifiers in this category allow you to open a file, perform a number of (read/write) operations on it, and close it.

	'''Note''' that you should check [[$ferr]] after every ~~modification of~~ the file (~~inclusive~~ opening it).		First of all you have to open a file using [[Fopen\|/fopen]]. When doing this, you have to specify a handle - in subsequent commands you can use this handle to refer to the open file. The handle is just a name that you, the scripter, can choose yourself. This is similar to how [[:Category:Socket\|socket]] names work.

			Each open file has a ''file pointer''. This file pointer is the current byte position in the file, and the read/write commands will always work from this position. Additionally, those commands will move the file pointer forward with as many bytes as they read/write. For example, if the file pointer is at byte 1055, and you use [[$fgetc]], then you will get the 1055th byte of the file, and the file pointer will move to 1056. When you've just opened the file, the file pointer is set to the start of the file (byte 0); you can manually move the pointer to another position in the file by using [[Fseek\|/fseek]].

			mIRC will lock an opened file from being accessed by other programs for as long as the file handle is open. After you've used a file, you '''have to''' close it again, using [[Fclose\|/fclose]]. That will write any changes you made to disk, and unlock the file.

			'''Note''' that you should check [[$ferr]] after every operation on the file (including opening it!).

	== Difference to /write and $read ==		== Difference to /write and $read ==

Zyberdog: better overview

2005-12-22T18:17:52Z

better overview

← Older revision		Revision as of 18:17, 22 December 2005
Line 17:		Line 17:
	#read this line (using $fread)		#read this line (using $fread)
	#close the file (using fclose) again		#close the file (using fclose) again


	That's obviously not efficient, as we don't need to close it after our first read. So using File Handling, we could directly do:		That's obviously not efficient, as we don't need to close it after our first read. So using File Handling, we could directly do:
	#open the file (using fopen)		#open the file (using fopen)

Zyberdog: test preview

2005-12-22T18:16:26Z

test preview

← Older revision		Revision as of 18:16, 22 December 2005
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	[[echo]] -a $read(my.txt,4) $read(my.txt,5)		[[echo]] -a $read(my.txt,4) $read(my.txt,5)
	Internally, mIRC would do following:		Internally, mIRC would do following:
	*open the file (using fopen)		#open the file (using fopen)
	*read the first line (using $fread - check [[$read]] for more details about it)		#read the first line (using $fread - check [[$read]] for more details about it)
	*move the pointer to the start of line 4 (using fseek)		#move the pointer to the start of line 4 (using fseek)
	*read this line (using $fread)		#read this line (using $fread)
	*close the file (using fclose)		#close the file (using fclose)
	*open the file again (using fopen)		#open the file again (using fopen)
	*move the pointer to the start of line 5 (using fseek)		#move the pointer to the start of line 5 (using fseek)
	*read this line (using $fread)		#read this line (using $fread)
	*close the file (using fclose) again		#close the file (using fclose) again
	That's obviously not efficient, as we don't need to close it after our first read. So using File Handling, we could directly do:		That's obviously not efficient, as we don't need to close it after our first read. So using File Handling, we could directly do:
	*open the file (using fopen)		#open the file (using fopen)
	*jump to line 4 (using fseek)		#jump to line 4 (using fseek)
	*read this line (using fread)		#read this line (using fread)
	*read the next line (and the pointer is automatically there after reading line 4 - using fread)		#read the next line (and the pointer is automatically there after reading line 4 - using fread)
	*close the file (using flose)		#close the file (using flose)
	If you want to read one or two lines only, there is no need to use this way, as $read is alot easier to handle, but if you have a file of e.g. 40mb and want to read 100 lines, there is a ''big'' difference between File Handling and $read (~ factor 10).		If you want to read one or two lines only, there is no need to use this way, as $read is alot easier to handle, but if you have a file of e.g. 40mb and want to read 100 lines, there is a ''big'' difference between File Handling and $read (~ factor 10).
	== Example ==		== Example ==

Albie: sp. accessible

2005-12-22T18:08:09Z

sp. accessible

← Older revision		Revision as of 18:08, 22 December 2005
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	== General Explanation ==		== General Explanation ==
	Using the commands and identifiers in this category allows you to modify a file directly. That means that mIRC opens a connection to the specified and locks this connection when you are opening a file using [[Fopen\|/fopen]]. At the same moment, a (file-)pointer is set to the start of the file. You can now read the character the pointer points to (either by using [[$fread]] that reads the entire line until the next [[$crlf]] or by using [[$fgetc]] that reads the "next" character only - note that the pointer is automatically moved to the begin of the next line / next character by using these identifiers) or move the pointer to another position in the file (by using [[Fseek\|/fseek]]). After you've modified you file, you '''have to''' close it again (to unlock it and so make it ~~accessable~~ by other applications) using [[Fclose\|/fclose]].		Using the commands and identifiers in this category allows you to modify a file directly. That means that mIRC opens a connection to the specified and locks this connection when you are opening a file using [[Fopen\|/fopen]]. At the same moment, a (file-)pointer is set to the start of the file. You can now read the character the pointer points to (either by using [[$fread]] that reads the entire line until the next [[$crlf]] or by using [[$fgetc]] that reads the "next" character only - note that the pointer is automatically moved to the begin of the next line / next character by using these identifiers) or move the pointer to another position in the file (by using [[Fseek\|/fseek]]). After you've modified you file, you '''have to''' close it again (to unlock it and so make it accessible by other applications) using [[Fclose\|/fclose]].

	'''Note''' that you should check [[$ferr]] after every modification of the file (inclusive opening it).		'''Note''' that you should check [[$ferr]] after every modification of the file (inclusive opening it).

Doomie: these -> this

2005-12-21T21:42:14Z

these -> this

← Older revision		Revision as of 21:42, 21 December 2005
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	== General Explanation ==		== General Explanation ==
	Using the commands and identifiers in ~~these~~ category allows you to modify a file directly. That means that mIRC opens a connection to the specified and locks this connection when you are opening a file using [[Fopen\|/fopen]]. At the same moment, a (file-)pointer is set to the start of the file. You can now read the character the pointer points to (either by using [[$fread]] that reads the entire line until the next [[$crlf]] or by using [[$fgetc]] that reads the "next" character only - note that the pointer is automatically moved to the begin of the next line / next character by using these identifiers) or move the pointer to another position in the file (by using [[Fseek\|/fseek]]). After you've modified you file, you '''have to''' close it again (to unlock it and so make it accessable by other applications) using [[Fclose\|/fclose]].		Using the commands and identifiers in this category allows you to modify a file directly. That means that mIRC opens a connection to the specified and locks this connection when you are opening a file using [[Fopen\|/fopen]]. At the same moment, a (file-)pointer is set to the start of the file. You can now read the character the pointer points to (either by using [[$fread]] that reads the entire line until the next [[$crlf]] or by using [[$fgetc]] that reads the "next" character only - note that the pointer is automatically moved to the begin of the next line / next character by using these identifiers) or move the pointer to another position in the file (by using [[Fseek\|/fseek]]). After you've modified you file, you '''have to''' close it again (to unlock it and so make it accessable by other applications) using [[Fclose\|/fclose]].

	'''Note''' that you should check [[$ferr]] after every modification of the file (inclusive opening it).		'''Note''' that you should check [[$ferr]] after every modification of the file (inclusive opening it).

Doomie: forgot a dot - hey, its a rime

2005-12-21T21:35:11Z

forgot a dot - hey, its a rime

← Older revision		Revision as of 21:35, 21 December 2005
Line 2:		Line 2:
	Using the commands and identifiers in these category allows you to modify a file directly. That means that mIRC opens a connection to the specified and locks this connection when you are opening a file using [[Fopen\|/fopen]]. At the same moment, a (file-)pointer is set to the start of the file. You can now read the character the pointer points to (either by using [[$fread]] that reads the entire line until the next [[$crlf]] or by using [[$fgetc]] that reads the "next" character only - note that the pointer is automatically moved to the begin of the next line / next character by using these identifiers) or move the pointer to another position in the file (by using [[Fseek\|/fseek]]). After you've modified you file, you '''have to''' close it again (to unlock it and so make it accessable by other applications) using [[Fclose\|/fclose]].		Using the commands and identifiers in these category allows you to modify a file directly. That means that mIRC opens a connection to the specified and locks this connection when you are opening a file using [[Fopen\|/fopen]]. At the same moment, a (file-)pointer is set to the start of the file. You can now read the character the pointer points to (either by using [[$fread]] that reads the entire line until the next [[$crlf]] or by using [[$fgetc]] that reads the "next" character only - note that the pointer is automatically moved to the begin of the next line / next character by using these identifiers) or move the pointer to another position in the file (by using [[Fseek\|/fseek]]). After you've modified you file, you '''have to''' close it again (to unlock it and so make it accessable by other applications) using [[Fclose\|/fclose]].

	'''Note''' that you should check [[$ferr]] after every modification of the file (inclusive opening it)		'''Note''' that you should check [[$ferr]] after every modification of the file (inclusive opening it).

	== Difference to /write and $read ==		== Difference to /write and $read ==

Doomie at 21:31, 21 December 2005

2005-12-21T21:31:10Z

← Older revision		Revision as of 21:31, 21 December 2005
Line 1:		Line 1:
	== General Explanation ==		== General Explanation ==
	Using the commands and identifiers in these category allows you to modify a file directly. That means that mIRC opens a connection to the specified and locks this connection when you are opening a file using [[Fopen\|/fopen]]. At the same moment, a (file-)pointer is set to the start of the file. You can now read the character the pointer points to (either by using [[$fread]] that reads the entire line until the next [[$crlf]] or by using [[$fgetc]] that reads the "next" character only - note that the pointer is automatically moved to the begin of the next line / next character by using these identifiers) or move the pointer to another position in the file (by using [[Fseek\|/fseek]]). After you've modified you file, you '''have to''' close it again (to unlock it and so make it accessable by other applications) using [[Fclose\|/fclose]].		Using the commands and identifiers in these category allows you to modify a file directly. That means that mIRC opens a connection to the specified and locks this connection when you are opening a file using [[Fopen\|/fopen]]. At the same moment, a (file-)pointer is set to the start of the file. You can now read the character the pointer points to (either by using [[$fread]] that reads the entire line until the next [[$crlf]] or by using [[$fgetc]] that reads the "next" character only - note that the pointer is automatically moved to the begin of the next line / next character by using these identifiers) or move the pointer to another position in the file (by using [[Fseek\|/fseek]]). After you've modified you file, you '''have to''' close it again (to unlock it and so make it accessable by other applications) using [[Fclose\|/fclose]].

			'''Note''' that you should check [[$ferr]] after every modification of the file (inclusive opening it)

	== Difference to /write and $read ==		== Difference to /write and $read ==

Doomie at 21:28, 21 December 2005

2005-12-21T21:28:04Z

← Older revision		Revision as of 21:28, 21 December 2005
Line 7:		Line 7:
	Internally, mIRC would do following:		Internally, mIRC would do following:
	*open the file (using fopen)		*open the file (using fopen)
			*read the first line (using $fread - check [[$read]] for more details about it)
	*move the pointer to the start of line 4 (using fseek)		*move the pointer to the start of line 4 (using fseek)
	*read this line (using $fread)		*read this line (using $fread)

Doomie at 21:17, 21 December 2005

2005-12-21T21:17:41Z

← Older revision		Revision as of 21:17, 21 December 2005
Line 8:		Line 8:
	*open the file (using fopen)		*open the file (using fopen)
	*move the pointer to the start of line 4 (using fseek)		*move the pointer to the start of line 4 (using fseek)
	*read this line using $fread		*read this line (using $fread)
	*close the file (using fclose)		*close the file (using fclose)
	*open the file again (using fopen)		*open the file again (using fopen)
	*move the pointer to the start of line 5 (using fseek)		*move the pointer to the start of line 5 (using fseek)
	*read this line using $fread		*read this line (using $fread)
	*close the file (using fclose) again		*close the file (using fclose) again
	That's obviously not efficient, as we don't need to close it after our first read. So using File Handling, we could directly do:		That's obviously not efficient, as we don't need to close it after our first read. So using File Handling, we could directly do:

Doomie at 21:16, 21 December 2005

2005-12-21T21:16:42Z

@@ Line 1: / Line 1: @@
 == General Explanation ==
+Using the commands and identifiers in these category allows you to modify a file directly. That means that mIRC opens a connection to the specified and locks this connection when you are opening a file using [[Fopen|/fopen]]. At the same moment, a (file-)pointer is set to the start of the file. You can now read the character the pointer points to (either by using [[$fread]] that reads the entire line until the next [[$crlf]] or by using [[$fgetc]] that reads the "next" character only - note that the pointer is automatically moved to the begin of the next line / next character by using these identifiers) or move the pointer to another position in the file (by using [[Fseek|/fseek]]). After you've modified you file, you '''have to''' close it again (to unlock it and so make it accessable by other applications) using [[Fclose|/fclose]].
 == Difference to /write and $read ==
+Contrary to this, the "usual" way to access a file ([[Write|/write]] and [[$read]] that is) work in another way. For example, if you want to echo line number 4 and 5 of a file, you would use:
 == Example ==
 [[Category:mIRC Help]]