[Groff] File Locking

[Robert Thorsby]

I've finally started one of those rainy day projects. I'm rewriting my 
Business Letterhead shell script.

It's progressed to the stage where, after I've written the draft 
letter, the script opens the input file in the text editor du jour and 
also opens the resulting postscript file in gv. Every time I hit "Save" 
in the text editor the script automagically re-runs the input file 
through groff and, of course, the "watch" switch in gv automagically 
reloads the updated postscript file. The result is a sort of groff 
version of WYSIWYG.

However, I don't know what would happen if I used the text editor 
"Save" twice in quick succession. In other words what would happen if 
my text editor is amending the input file on the "second" occasion at 
the same time as groff is processing it as a result of the "first" 
save?

Can anyone tell me what is likely to happen? I have no idea how to 
create the problem deliberately.

TIA,
Robert Thorsby