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<div class="moz-cite-prefix">On 22/08/2013 15:20, m. allan noah
wrote:<br>
</div>
<blockquote
cite="mid:CAKO8m0CB91+X9b0ryMxwhv46pOZ7b9Zf4K8+hNq6Um4UP9enng@mail.gmail.com"
type="cite">
<div dir="ltr">
<div>We have a debugging library which is part of sane-backends.
It allows you to set an environment variable, and which causes
the backend to print messages to STDERR. If your backend is
part of sane-backends, you can use this library. If you
backend is outside of sane-backends, you can certainly setup
something similar in your backend. You should not have to
recompile the frontend.<br>
<br>
</div>
allan<br>
</div>
<div class="gmail_extra"><br>
<br>
<div class="gmail_quote">On Thu, Aug 22, 2013 at 6:46 AM, <span
dir="ltr"><<a moz-do-not-send="true"
href="mailto:YiHao@rst.ricoh.com" target="_blank">YiHao@rst.ricoh.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex"><br>
Dear Sir or Madam:<br>
<br>
I want to know,<br>
How can I debug the sane-backend by frontend(e.g.
scanimage),<br>
<br>
How to enter the backend's breakpoint,<br>
Do I need to compile the frontend if I want to know whether
the backend<br>
receives the Frontend command.<br>
<br>
<br>
<br>
<br>
<br>
Can you give me some advise, Thank you.<br>
Best Regard<br>
<br>
Yours Sincerely, Yihao<br>
<span class="HOEnZb"><font color="#888888"><br>
<br>
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</font></span></blockquote>
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<br>
<br clear="all">
<br>
-- <br>
"The truth is an offense, but not a sin"
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<br>
</blockquote>
Hello,<br>
<br>
you may also consider compiling with debug option, by default
the -O2 option ins SANE build system will optimize out many
information. When debugging I add the -ggdb option to configure to
be able to step into code with gdb:<br>
CFLAGS="-ggdb" ./configure \<br>
--prefix=/usr \<br>
--sysconfdir=/etc \<br>
--libdir=/usr/lib64 \<br>
--enable-parport-directio \<br>
--enable-pnm-backend \<br>
--enable-libusb_1_0 \<br>
--enable-pthread \<br>
--enable-locking \<br>
--with-group=scanner \<br>
--without-snmp<br>
<br>
Then you can debug your backend even used through a frontend like
xsane with:<br>
<br>
gdb /usr/bin/xsane<br>
<br>
Then you can set breakpoint, gdb will warned if function aren't
resolved yet, but it will work here a sample session for the genesys
backend:<br>
<br>
(gdb) b genesys_sane_start<br>
Function "genesys_sane_start" not defined.<br>
Make breakpoint pending on future shared library load? (y or [n]) y<br>
Breakpoint 3 (genesys_sane_start) pending.<br>
(gdb) r<br>
Starting program: /usr/bin/xsane <br>
warning: Could not load shared library symbols for linux-vdso.so.1.<br>
Do you need "set solib-search-path" or "set sysroot"?<br>
Traceback (most recent call last):<br>
File
"/usr/share/gdb/auto-load/usr/lib64/libgobject-2.0.so.0.3600.4-gdb.py",
l<br>
ine 9, in <module><br>
from gobject import register<br>
File "/usr/share/glib-2.0/gdb/gobject.py", line 3, in
<module><br>
import gdb.backtrace<br>
ImportError: No module named backtrace<br>
[Thread debugging using libthread_db enabled]<br>
Using host libthread_db library "/lib64/libthread_db.so.1".<br>
[New Thread 0x7fffeb5cb700 (LWP 2593)]<br>
<br>
Breakpoint 2, sane_start (h=0x7a43a0) at genesys-s.c:48<br>
<br>
Regards,<br>
Stef<br>
<br>
<br>
<br>
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