Modules/FileSystem/file/isReadable: Difference between revisions
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(Created page with "__NOTOC__ This function returns whether a stream is readable. If a stream is not readable, then all read operations should result in nil operations (they will return zero bytes read or false if value reading). This state should be immutable across the lifetime of a file/stream class. ==Syntax== <syntaxhighlight lang="lua"> boolean file:isReadable () </syntaxhighlight> ==Returns== Returns '''true''' if the file/stream is readable, '''false''' otherwise. ==Example== <se...") |
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<pageclass class="#3cc882" subcaption="File function"></pageclass> | |||
__NOTOC__ | __NOTOC__ | ||
This function returns whether a stream is readable. If a stream is not readable, then all read operations should result in nil operations (they will return zero bytes read or false if value reading). This state should be immutable across the lifetime of a file/stream class. | This function returns whether a stream is readable. If a stream is not readable, then all read operations should result in nil operations (they will return zero bytes read or false if value reading). This state should be immutable across the lifetime of a file/stream class. | ||
Latest revision as of 03:14, 23 January 2022
This function returns whether a stream is readable. If a stream is not readable, then all read operations should result in nil operations (they will return zero bytes read or false if value reading). This state should be immutable across the lifetime of a file/stream class.
Syntax
boolean file:isReadable ()
Returns
Returns true if the file/stream is readable, false otherwise.
Example
Click to collapse [-]
ClientThis snippet is the counterpart of the file.isWritable example. It attempts to read the header from the file, but throws an exception if it cannot be read from.
local function readHeader( theFile )
-- Check whether we can read anything from the file.
if not ( theFile:isReadable() ) then
error( "fatal error: file cannot be read from" );
end
-- Read the generic header back into the engine.
local headerInfo = {
chunkSize = theFile:readUInt(),
version = theFile:readFloat(),
isRaw = theFile:readBoolean()
};
-- Return the header information.
return headerInfo;
end