Additional Topics > External Development Guide > IDLInternals - Files and Input Output > Detecting End of File with IDL_FileEOF()

# Detecting End of File with IDL_FileEOF()

## IDL_FileEOF()

int IDL_FileEOF(int unit)

The IDL_FileEOF() function returns TRUE if the file specified by the Logical Unit Number unit is at EOF, and FALSE otherwise.

### unit

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