Additional Topics > External Development Guide > IDLInternals - Files and Input Output > Closing Files with IDL_FileClose()

# Closing Files with IDL_FileClose()

Files are closed using the IDL_FileClose() function.

## IDL_FileClose()

void IDL_FileClose(int argc, IDL_VPTR *argv, char *argk)

### argc

The number of arguments in argv.

### argv

The arguments to the close function. These should be scalar integer values giving the Logical Unit Numbers of the file units to close.

### argk

Keywords. Set this argument to NULL.