..  _ftyp:

FTYP
====

+----------+------------------------------------------------------------------+
| Syntax   | FTYP [(#channel)] or                                             |
|          |                                                                  |
|          | FTYP (\\file) (Toolkit II and THOR only)                         |
+----------+------------------------------------------------------------------+
| Location | Toolkit II, THOR XVI, BTool                                      |
+----------+------------------------------------------------------------------+

This function returns the file type of a file which is already open
as #channel (the default channel is #3) or else the second variant can
be used (which supports the Toolkit II default data device and
sub-directories) to check a given file.

The file type is one byte in the
file header which by convention represents the type of the file. There
are only four standard types:

- FTYP = 1 are executable jobs (normally suffixed \_exe);
- FTYP = 2 are Sinclair Relocatable Object File (SROFF) modules (normally suffixed \_REL);
- FTYP = 255 are sub-directories on level-2 and level-3 drivers;
- FTYP = 0 are everything else.

However, some programmers use their own file
types for their applications, for example:

- FTYP = 2 may also signify sub-directory declaration files used by Ralf Biedermann's flp utility and Hirschbiegel drivers;
- FTYP = 3 are sub-directories on THOR computers.
- FTYP = 4represents font files used by the PAINTER.
- FTYP = 5 are pattern files used by the PAINTER.
- FTYP = 6 or 11 are compressed screens generated by the PAINTER.
- FTYP = 70 is used to represent separation files from packages distributed by the Intergroup Freeware Exchange.

**WARNING**

Sometimes machine code files (Toolkits, for instance) which should be
loaded with LBYTES, LRESPR etc. have the file type 1. Executing such a
file will lead to a crash in most cases, UNJOB changes the file type
back to 0. Authors with a lot of skill write machine code which can be
either executed as a job or loaded as a resident command executing the
job from memory when called.

**CROSS-REFERENCE**

See :ref:`headr` for reading the whole file header
and :ref:`ex` for executing jobs.
:ref:`file-type` does the same as
:ref:`ftyp` but has a slightly different syntax.