sane-project-backends/README.darwin

SANE and Darwin (Mac OS X)
--------------------------

Building:
---------
You may get the message: "gcc: Internal compiler error: program cc1obj got
fatal signal 11". That's not a bug in SANE. Probably a compiler or hardware
problem.  The error usually occurs in canon.c because that's the most complex
backend (at least concerning compilation). If you can't update your compiler,
try to reduce optimization (e.g. CFLAGS="-O1" ./configure). Another
work-around: Disable the canon backend in backend/Makefile.in (look at
PRELOADABLE_BACKENDS) and rerun configure.

General:
--------
If scanimage -L (or any other frontend) stops with a segmentation fault in the
sm3600 backend, disable sm3600 in dll.conf if you don't need it.

Backends that use the function "fork" may not work at least with USB scanners.
That's a limitation of MacOS X (doesn't use file descriptors for USB access).
Some backends have been modified to use threads on MAcOS X qand should
work. Others don't use fork at all. Both types of backends should work with
MacOS X. Changing the backends to use threads is an ongoing effort.

SCSI-scanners and Firewire scanners:
------------------------------------
There is support for SCSI and Firewire scanners but hasn't had much
testing. Please send failure and success reports to the sane-devel mailing
list. At least the Epson Perfection 1640SU and the CANON IX-06015C (CanoScan
600) are reported to work.

sane-find-scanner is not able to find SCSI scanners on MacOS X yet.

USB-scanners:
-------------
Work with libusb. Very limited testing until now. Try "sane-find-scanner -v -v"
and report success or failure to the SANE mailing list. At least the following
scanners are known to work: UMAX Astra 1220U and 2000U, Epson Perfection 1640SU
and 2450 Photo.

There are some known problems with libusb:

- Older libusb versions return a wrong number of bytes written. Most backends
  will return an error and won't work. Update your version of libusb.

- Sometimes libusb doesn't detect your scanner. Try setting the environment
  variable SANE_DEBUG_SANEI_USB to 255 (e.g. "setenv SANE_DEBUG_SANEI_USB 255"
  or "export SANE_DEBUG_SANEI_USB=255) before running scanimage -L.

Parport-scanners:
-----------------
I don't have any information about these. Please contact me or the SANE mailing
list if you succeeded in using one of these.

2003-12-26 Henning Meier-Geinitz <henning@meier-geinitz.de>