MTA:Eir/FileSystem/file/isWritable: Difference between revisions
Jump to navigation
Jump to search
(Created page with "__NOTOC__ This function returns whether a stream is writable. If a stream is not writable, then all write operations should result in nil operations (they will return zero bytes ...") |
mNo edit summary |
||
| Line 4: | Line 4: | ||
==Syntax== | ==Syntax== | ||
<syntaxhighlight lang="lua"> | <syntaxhighlight lang="lua"> | ||
boolean file | boolean file:isWritable () | ||
</syntaxhighlight> | </syntaxhighlight> | ||
| Line 16: | Line 16: | ||
local function writeHeader( theFile, headerInfo ) | local function writeHeader( theFile, headerInfo ) | ||
-- Check whether we can write things into the file. | -- Check whether we can write things into the file. | ||
if not ( theFile | if not ( theFile:isWritable() ) then | ||
error( "fatal error: stream is not writable" ); | error( "fatal error: stream is not writable" ); | ||
end | end | ||
-- Write a generic header structure. | -- Write a generic header structure. | ||
theFile | theFile:writeUInt( headerInfo.chunkSize ); | ||
theFile | theFile:writeFloat( headerInfo.version ); | ||
theFile | theFile:writeBoolean( headerInfo.isRaw ); | ||
end | end | ||
</syntaxhighlight> | </syntaxhighlight> | ||
</section> | </section> | ||
{{:MTA:Eir/FileSystem/file/functions}} | {{:MTA:Eir/FileSystem/file/functions}} | ||
Latest revision as of 23:50, 16 January 2022
This function returns whether a stream is writable. If a stream is not writable, then all write operations should result in nil operations (they will return zero bytes written). This state should be immutable across the lifetime of a file/stream class.
Syntax
boolean file:isWritable ()
Returns
Returns true if the file/stream is writable, false otherwise.
Example
Click to collapse [-]
ClientThis snippet implements a file function that makes sure the file it has been passed to for writing actually supports writing.
local function writeHeader( theFile, headerInfo )
-- Check whether we can write things into the file.
if not ( theFile:isWritable() ) then
error( "fatal error: stream is not writable" );
end
-- Write a generic header structure.
theFile:writeUInt( headerInfo.chunkSize );
theFile:writeFloat( headerInfo.version );
theFile:writeBoolean( headerInfo.isRaw );
end