Re: Setjmp(), longjmp() in gnuplot

[<tim...@en...>]

Ethan Merritt wrote:

>On Friday 24 June 2005 01:42 pm, Timoth=C3=A9e Lecomte wrote:
> =20
>
>>Ethan Merritt wrote:
>>   =20
>>
>> The remaining problem is that setjmp/longjmp were=20
>>designed for C, not C++.
>>   =20
>>
>I see. So your new driver is C++ only?=20
>
It is C++ only, but until now I have managed to mix C and C++ without=20
problems. I have added a few lines in configure.in (for both c++ and=20
wxwidgets), written my terminal as a common wxt.trm whith C++ functions=20
defined in an external wxt.cpp file.

>That is already a potential problem since the rest of the gnuplot is dis=
tinctly not C++ code.
>I fear it will limit the number of platforms on which your new
>driver will actually compile and link into gnuplot successfully.
>We'll find out, I guess.
> =20
>
According to c++ documentation, it should not be a problem (provided we=20
have a c++ compiler for the desired platform ;-). The C and C++ files=20
are compiled by their respective compilers, and then the C++ one link=20
everything. It works at least on my machine.

>>So if I initialize the =20
>>longjump when creating my terminal thread, it doesn't delete the old=20
>>window but open a new one when longjmp is used ! However, it does not=20
>>segfault... So the solution may be to check if another window is opened=
=20
>>and destroy it before to continue. That doesn't seem very efficient.
>>   =20
>>
>
>Can't you do the same thing as the x11 driver?  When you send a new
>plot command the driver looks to see if there is an existing window and =
if
>so uses it.  If there is no existing window then it opens a new one.
>See the difference?  You check for an old window, but instead of destoyi=
ng
>it you just use it explicitly for the new plot also.
> =20
>
I think that all this setjmp/longjmp stuff makes it difficult. I've=20
tried some combinations, and even if objects are not destroyed, they are=20
not usable ! I can't tell anything to the frame.

On the other hand, I wrote things so that when user closes the terminal=20
window, in fact he only hides it, so on next plot it is still available=20
and it is asked to unhide. But setjmp/longjmp are not the same problem=20
unfortunately !

Timoth=C3=A9e

Timoth=C3=A9e