FileOpen: Difference between revisions
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===Required Arguments=== | ===Required Arguments=== | ||
*'''filePath:''' | *'''filePath:''' The [[filepath]] of the file in the following format: '''":resourceName/path"'''. 'resourceName' is the name of the resource the file is in, and 'path' is the path from the root directory of the resource to the file. | ||
:For example, if there is a file named 'coolObjects.txt' in the resource 'objectSearch', it can be opened from another resource this way: ''fileOpen(":objectSearch/coolObjects.txt")''. | :For example, if there is a file named 'coolObjects.txt' in the resource 'objectSearch', it can be opened from another resource this way: ''fileOpen(":objectSearch/coolObjects.txt")''. | ||
:If the file is in the current resource, only the file path is necessary, e.g. ''fileOpen("coolObjects.txt")''. | :If the file is in the current resource, only the file path is necessary, e.g. ''fileOpen("coolObjects.txt")''. |
Revision as of 16:57, 16 September 2009
Opens an existing file for reading and writing.
Note: The file functions should not be used to implement configuration files. It is encouraged to use the XML functions for this instead.
Syntax
file fileOpen ( string filePath [, bool readOnly = false ])
Required Arguments
- filePath: The filepath of the file in the following format: ":resourceName/path". 'resourceName' is the name of the resource the file is in, and 'path' is the path from the root directory of the resource to the file.
- For example, if there is a file named 'coolObjects.txt' in the resource 'objectSearch', it can be opened from another resource this way: fileOpen(":objectSearch/coolObjects.txt").
- If the file is in the current resource, only the file path is necessary, e.g. fileOpen("coolObjects.txt").
Optional Arguments
- readOnly: By default, the file is opened with reading and writing access. You can specify true for this parameter if you only need reading access.
Returns
If successful, returns a file handle for the file. Otherwise returns false (f.e. if the file doesn't exist).
Example
This example opens the file test.txt that is in the root of the current resource, and outputs its contents to the console.
local hFile = fileOpen("test.txt", true) -- attempt to open the file (read only) if hFile then -- check if it was successfully opened local buffer while not fileIsEOF(hFile) do -- as long as we're not at the end of the file... buffer = fileRead(hFile, 500) -- ... read the next 500 bytes... outputConsole(buffer) -- ... and output them to the console end fileClose(hFile) -- close the file once we're done with it else outputConsole("Unable to open test.txt") end
Notice that you can't simply do buffer = fileRead("test.txt", 500). Instead, file functions operate on a file handle, which is a special object representing an open file. fileOpen gives us such a handle.
It is also important to remember to close a file after you've finished all your operations on it, especially if you've been writing to the file. If you don't close a file and your resource crashes, all changes to the file may be lost.
See Also
- fileClose
- fileCopy
- fileCreate
- fileDelete
- fileExists
- fileFlush
- fileGetPath
- fileGetPos
- fileGetSize
- fileIsEOF
- fileOpen
- fileRead
- fileRename
- fileSetPos
- fileWrite