eval really isn't reliable here. The program may very well start in X if X is running, even if it is not called under X.
IMHO, you really should check for $ENV{DISPLAY}, if X is running and DISPLAY is not set it is really the user's problem, not yours.
Some gui toolkits have their own internal checks for this stuff, gtk has something like init_check() (wondering if it can run or not) maybe you could find something similar in Tk. This seems too low-level though for whatever the gui toolkit not to have.
But again, until then, use $ENV{DISPLAY}. If the user doesn't have it set and has X running, i can bet it wouldn't be just your application he would have problems with.
--
| [reply] |
$ENV{DISPLAY} not being set if X is running is only one part of the problem - and the less problematic one, because in that case, it runs the command line version. The other problem is $ENV{DISPLAY} being set and X not running. Then it will try to launch an X application.
| [reply] |
So can you not check for BOTH a non-empty DISPLAY *and* check the process table (via ps or whatever is handy) for the X process?
| [reply] |