Re: Is gp_exit() used at exit in current gnuplot?

[Tatsuro M. <tma...@ya...>]

----- Original Message -----

> From: sfeam 
> To: gnuplot-beta Tatsuro MATSUOKA 
> Cc: 
> Date: 2017/2/28, Tue 13:51
> Subject: Re: Is gp_exit() used at exit in current gnuplot?
> 
> On Tuesday, 28 February 2017 10:38:04 AM Tatsuro MATSUOKA wrote:
>>  This is related to bug #1913.
>> 
>>  In stdfn.c
>> 
>>  there stated
>> 
>> 
>>  /* Calls the cleanup functions registered using gp_atexit().
>>   * Normally gnuplot should be exited using gp_exit(). In some cases, this 
> is not
>>   * possible (notably when returning from main(), where some compilers get
>>   * confused because they expect a return statement at the very end. In that
>>   * case, gp_exit_cleanup() should be called before the return statement.
>>   */
>> 
>> 
>>  *****************************
>>  Normally gnuplot should be exited using gp_exit().
>>  ***************************
> 
> I think the intended meaning is
> "If you were going to terminate the program by calling exit(), don't do 
> that.
> Instead call gp_exit()."  
> 
> However the normal exit from main() in a C language program is by 
> "return", not "exit()". 
> So gnuplot's main() routine does not  call either exit() or gp_exit().  
> Instead it calls
> gp_exit_cleanup() followed by "return". 
> Thus it does exactly what the comment describes.  
> 
>>  Excuse me for my writing without reading the code in detail.
>>  gp_exit() seems to be used in many place in the code.
>>  Therefore gp_exit() is surely used in current gnuplot.
> 
> Yes.  For example If you say
> gnuplot>  exit gnuplot
> then it calls gp_exit().
> 
>>  However, "gnuplot> exit" does not use gp_exit() as written in 
> the
>>  previous post.
>> 
>>  I feel that the message
>> 
>>  Gnuplot not exited using gp_exit(). Exit handlers may not work correctly!
>> 
>>  in debug_exit_handler in stdfn.c is better to be modified.
> 
> I think you are correct that the message is not accurate.
> It would be better to say 
> "Gnuplot not exiting normally. Exit handlers may not work correctly!"
> gp_exit() is one way of exiting normally, but exiting by return from main()
> is also a way of exiting normally.
> 
> In your case (Bug 1913) I guess neither of these normal ways to exit is 
> happening.
> Instead gnuplot is killed by the operating system because you hit  the "X 
> button".
> 
>     Ethan
> 
> 
> 
Thank you for your comprehensive explanation.
I hope that message  in debug_exit_handler will be modified as you indicaded

"Gnuplot not exiting normally. Exit handlers may not work correctly!"

Tatsuro