In OpenOffice Basic on a Linux system, MailMerge.Execute() with
OutputType=com.sun.star.text.MailMergeType.PRINTER hangs OOo on attempting to
exit; whereas when run with OutputType set to
com.sun.star.text.MailMergeType.FILE, the program exits fine. Note: The mail
merge itself runs perfectly fine and outputs to the printer without a problem,
it's just that "soffice" does not ever exit and needs to be send a SIGTERM to quit.

And here's the kicker... if I run a copy of OOo from the command line (in the
background or invoked from another shell: e.g. "soffice &"), then the invocation
of soffice running the macro DOES exit, and I can still exit the first soffice
invocation without a problem... I hope this fact provides a clue as to what
might be going wrong.

The following code snippet is the core of what is used. I'll post the whole
program as an attachment in a follow on.

oDbContext = CreateUnoService("com.sun.star.sdb.DatabaseContext")
oDbInstance = oDbContext.createInstance()
oDbContext.registerObject(sDbName, oDbInstance)
oDbInstance.URL = "sdbc:flat:" + aDbURL.Protocol + aDbURL.Path

oMailMerge = CreateUnoService("com.sun.star.text.MailMerge")
oMailMerge.DataSourceName = sDbName
oMailMerge.DocumentURL = aDocURL.Main
oMailMerge.CommandType = com.sun.star.sdb.CommandType.TABLE
oMailMerge.Command = sDbName
oMailMerge.OutputType = com.sun.star.text.MailMergeType.PRINTER
oMailMerge.SinglePrintJobs = False  ' Set the default, just in case...

oDbInstance.setPropertyValue("Info", mDbProperties())
oDbConnection = oDbInstance.getConnection("", "")
oMailMerge.ActiveConnection = oDbConnection
	
Dim w() As com.sun.star.beans.NamedValue  ' Empty placeholder for invocation
oMailMerge.execute(w)

When I run the exact same code, but with
MailMerge.OutputType=com.sun.star.text.MailMergeType.FILE, it exits fine after
completing:

When it's hung, there are several soffices instantiated, e.g. (ps af):

 7268 pts/0 S 0:07  \_ /usr/local/OO/program/soffice.bin [...]
 7288 pts/0 S 0:00      \_ /usr/local/OO/program/soffice.bin [...]
 7289 pts/0 S 0:00          \_ /usr/local/OO/program/soffice.bin [...]
 7291 pts/0 S 0:00          \_ /usr/local/OO/program/soffice.bin [...]
 7292 pts/0 S 0:00          \_ /usr/local/OO/program/soffice.bin [...]
 7299 pts/0 S 0:00          \_ /usr/local/OO/program/soffice.bin [...]

Is there any instance of soffice.bin that I can give debug information on that
would be particularly useful? They are variously waiting on pipes (a read of
which returns EAGAIN) and writing to other pipes. I can provide detailed system
call trace information if that would help figure out what was going on.

N.B. This issue is similar to another one reported for Solaris (Issue #23426),
but it doesn't actually crash on Linux, it just hangs... and it exhibits the
behaviour discussed above when there is already a copy of soffice running.