NAME
    Open -- Open a file for input or output

SYNOPSIS
    file = Open( name, accessMode )
    D0           D1    D2

    BPTR Open(STRPTR, LONG)

FUNCTION
    The named file is opened and a file handle returned.  If the
    accessMode is MODE_OLDFILE, an existing file is opened for reading
    or writing. If the value is MODE_NEWFILE, a new file is created for
    writing. MODE_READWRITE opens a file with an shared lock, but
    creates it if it didn't exist.  Open types are documented in the
    <dos/dos.h> or <libraries/dos.h> include file.

    The 'name' can be a filename (optionally prefaced by a device
    name), a simple device such as NIL:, a window specification such as
    CON: or RAW: followed by window parameters, or "*", representing the
    current window.  Note that as of V36, "*" is obsolete, and CONSOLE:
    should be used instead.

    If the file cannot be opened for any reason, the value returned
    will be zero, and a secondary error code will be available by
    calling the routine ioerr().

INPUTS
    name       - pointer to a null-terminated string
    accessMode - integer

RESULTS
    file - BCPL pointer to a file handle

SEE ALSO
    close(), changemode(), namefromfh(), parentoffh(), examinefh()