FileSetPos: Difference between revisions
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(New page: number fileSetPos ( file, number offset ) Sets the current read/write position in the file. Offset is number of bytes from beginning of file. Returns where the offset was actually set at....) |
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__NOTOC__ | |||
{{Server client function}} | |||
Sets the current read/write position in the file. | Sets the current read/write position in the file. | ||
==Syntax== | |||
<syntaxhighlight lang="lua"> | |||
int fileSetPos ( file theFile, int offset ) | |||
</syntaxhighlight> | |||
{{OOP||[[file]]:setPos|pos|fileGetPos}} | |||
===Required Arguments=== | |||
*'''theFile:''' The file handle of which you want to change the read/write position. | |||
*'''offset:''' The new position. This is the number of bytes from the beginning of the file. If this value is larger than the file size, it is limited to 52,428,800 bytes (50 MB). | |||
===Returns=== | |||
Returns where the offset was actually set at. I.e. if '''offset''' was past the end of the file, it will be set at the end of the file, and this position will be returned. Returns ''false'' in case of failure (e.g. the specified file handle is invalid). | |||
==Example== | |||
This example opens a binary file and prints the value of the byte at position 8 to the console. | |||
<syntaxhighlight lang="lua"> | |||
local hFile = fileOpen("test.dat") -- attempt to open the file | |||
if hFile then -- check if it succeeded | |||
fileSetPos(hFile, 8) -- set the read/write position | |||
local readByte = fileRead(hFile, 1) -- read one byte from this position | |||
outputConsole("Byte at position 8 = " .. string.byte(readByte)) -- output it | |||
fileClose(hFile) -- close the file | |||
else | |||
outputConsole("Unable to open test.dat") | |||
end | |||
</syntaxhighlight> | |||
==See Also== | |||
{{File functions}} | |||
[[pt-br:fileSetPos]] | |||
Latest revision as of 20:03, 20 December 2023
Sets the current read/write position in the file.
Syntax
int fileSetPos ( file theFile, int offset )
OOP Syntax Help! I don't understand this!
- Method: file:setPos(...)
- Variable: .pos
- Counterpart: fileGetPos
Required Arguments
- theFile: The file handle of which you want to change the read/write position.
- offset: The new position. This is the number of bytes from the beginning of the file. If this value is larger than the file size, it is limited to 52,428,800 bytes (50 MB).
Returns
Returns where the offset was actually set at. I.e. if offset was past the end of the file, it will be set at the end of the file, and this position will be returned. Returns false in case of failure (e.g. the specified file handle is invalid).
Example
This example opens a binary file and prints the value of the byte at position 8 to the console.
local hFile = fileOpen("test.dat") -- attempt to open the file
if hFile then -- check if it succeeded
fileSetPos(hFile, 8) -- set the read/write position
local readByte = fileRead(hFile, 1) -- read one byte from this position
outputConsole("Byte at position 8 = " .. string.byte(readByte)) -- output it
fileClose(hFile) -- close the file
else
outputConsole("Unable to open test.dat")
end