Additional Topics > External Development Guide > IDLInternals - Files and Input Output > Flushing Buffered Data

# Flushing Buffered Data

## IDL_FileFlushUnit()

int IDL_FileFlushUnit(int unit)

File data might be buffered in system memory in order to boost input/output performance. The IDL_FileFlushUnit() function forces any buffered data for the file specified by the Logical Unit Number unit to be written out.

### unit

The Logical Unit Number (LUN) of the file in question.