View source for Category:File Handling

== 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]].

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

== 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:        
 [[echo]] -a $read(my.txt,4) $read(my.txt,5)
Internally, mIRC would do following:
*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) 
*read this line (using $fread)
*close the file (using fclose)
*open the file again (using fopen)
*move the pointer to the start of line 5 (using fseek) 
*read this line (using $fread)
*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:
*open the file (using fopen)
*jump to line 4 (using fseek)
*read this line (using fread)
*read the next line (and the pointer is automatically there after reading line 4 - using fread)
*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).
== Example ==


[[Category:mIRC Help]]