diff mbox series

fortran/intrinsic.texi: Improve SIGNAL intrinsic entry (was: [patch] fortran/intrinsic.texi: Add 'passed by value' to signal handler)

Message ID 33a8ad77-3ef6-47e2-a6ad-6b480d21c141@codesourcery.com
State Accepted
Headers
Series fortran/intrinsic.texi: Improve SIGNAL intrinsic entry (was: [patch] fortran/intrinsic.texi: Add 'passed by value' to signal handler) |

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Commit Message

Tobias Burnus Oct. 17, 2023, 7:47 a.m. UTC 
  Hi Harald,

On 16.10.23 20:31, Harald Anlauf wrote:
> Hi Tobias,
>
> Am 16.10.23 um 19:11 schrieb Tobias Burnus:
>> OK for mainline?
>
> I think the patch qualifies as obvious.
>
> While at it, you might consider removing the comment a few lines below
> the place you are changing,
>
> @c TODO: What should the interface of the handler be?  Does it take
> arguments?
>
> and enhance the given example by e.g.:

Updated version attached – I will commit it later today, unless anyone
has follow-up suggestions before.

Thanks for the suggestions,

Tobias
-----------------
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Comments

Harald Anlauf Oct. 17, 2023, 5:02 p.m. UTC | #1 
Tobias,

your latest patch - which you already pushed - removes the
intrinsic declaration of signal.

This can lead to a user's confusion and undesired results when
the code is compiled e.g. with -std=f2018, because

   call signal (10, 1)  ! 10 = SIGUSR1 and 1 = SIG_IGN (on some systems)

could be mapped to the wrong external instead of the
libgfortran function _gfortran_signal_sub_int etc., or you
could get other compile-time errors with the example code.

I strongly recommend to restore the intrinsic declaration.

Cheers,
Harald

Am 17.10.23 um 09:47 schrieb Tobias Burnus:
> Hi Harald,
> 
> On 16.10.23 20:31, Harald Anlauf wrote:
>> Hi Tobias,
>>
>> Am 16.10.23 um 19:11 schrieb Tobias Burnus:
>>> OK for mainline?
>>
>> I think the patch qualifies as obvious.
>>
>> While at it, you might consider removing the comment a few lines below
>> the place you are changing,
>>
>> @c TODO: What should the interface of the handler be?  Does it take
>> arguments?
>>
>> and enhance the given example by e.g.:
> 
> Updated version attached – I will commit it later today, unless anyone
> has follow-up suggestions before.
> 
> Thanks for the suggestions,
> 
> Tobias
> -----------------
> Siemens Electronic Design Automation GmbH; Anschrift: Arnulfstraße 201, 
> 80634 München; Gesellschaft mit beschränkter Haftung; Geschäftsführer: 
> Thomas Heurung, Frank Thürauf; Sitz der Gesellschaft: München; 
> Registergericht München, HRB 106955
Tobias Burnus Oct. 17, 2023, 5:36 p.m. UTC | #2 
Hi Harald,

On 17.10.23 19:02, Harald Anlauf wrote:
> your latest patch - which you already pushed - removes the
> intrinsic declaration of signal.

Only to 'signal' or also to 'sleep'? I have now added both in the attach
patch.

(Not yet committed.)

Tobias
-----------------
Siemens Electronic Design Automation GmbH; Anschrift: Arnulfstraße 201, 80634 München; Gesellschaft mit beschränkter Haftung; Geschäftsführer: Thomas Heurung, Frank Thürauf; Sitz der Gesellschaft: München; Registergericht München, HRB 106955
Harald Anlauf Oct. 17, 2023, 6:05 p.m. UTC | #3 
Hi Tobias,

On 10/17/23 19:36, Tobias Burnus wrote:
> Hi Harald,
>
> On 17.10.23 19:02, Harald Anlauf wrote:
>> your latest patch - which you already pushed - removes the
>> intrinsic declaration of signal.
>
> Only to 'signal' or also to 'sleep'? I have now added both in the attach
> patch.

you are right: both should be declared as intrinsic.

Thanks,
Harald

> (Not yet committed.)
>
> Tobias
> -----------------
> Siemens Electronic Design Automation GmbH; Anschrift: Arnulfstraße 201,
> 80634 München; Gesellschaft mit beschränkter Haftung; Geschäftsführer:
> Thomas Heurung, Frank Thürauf; Sitz der Gesellschaft: München;
> Registergericht München, HRB 106955
diff mbox series

Patch

fortran/intrinsic.texi: Improve SIGNAL intrinsic entry

gcc/fortran/ChangeLog:

	* intrinsic.texi (signal): Mention that the argument
	passed to the signal handler procedure is passed by reference.
	Extend example.

diff --git a/gcc/fortran/intrinsic.texi b/gcc/fortran/intrinsic.texi
index 6c7ad03a02c..fe446fc8a9d 100644
--- a/gcc/fortran/intrinsic.texi
+++ b/gcc/fortran/intrinsic.texi
@@ -13168,10 +13168,10 @@  end program test_sign
 @table @asis
 @item @emph{Description}:
 @code{SIGNAL(NUMBER, HANDLER [, STATUS])} causes external subroutine
-@var{HANDLER} to be executed with a single integer argument when signal
-@var{NUMBER} occurs.  If @var{HANDLER} is an integer, it can be used to
-turn off handling of signal @var{NUMBER} or revert to its default
-action.  See @code{signal(2)}.
+@var{HANDLER} to be executed with a single integer argument passed by
+value when signal @var{NUMBER} occurs.  If @var{HANDLER} is an integer,
+it can be used to turn off handling of signal @var{NUMBER} or revert to
+its default action.  See @code{signal(2)}.
 
 If @code{SIGNAL} is called as a subroutine and the @var{STATUS} argument
 is supplied, it is set to the value returned by @code{signal(2)}.
@@ -13197,19 +13197,25 @@  Subroutine, function
 @item @var{STATUS} @tab (Optional) @var{STATUS} shall be a scalar
 integer. It has @code{INTENT(OUT)}.
 @end multitable
-@c TODO: What should the interface of the handler be?  Does it take arguments?
 
 @item @emph{Return value}:
 The @code{SIGNAL} function returns the value returned by @code{signal(2)}.
 
 @item @emph{Example}:
 @smallexample
+module m_handler
+contains
+  ! POSIX.1-2017:  void (*func)(int)
+  subroutine handler_print(signum) bind(C)
+    use iso_c_binding, only: c_int
+    integer(c_int), value :: signum
+    print *, 'handler_print invoked with signum =', signum
+  end subroutine
+end module
 program test_signal
-  intrinsic signal
-  external handler_print
-
-  call signal (12, handler_print)
-  call signal (10, 1)
+  use m_handler
+  call signal (12, handler_print)  ! 12 = SIGUSR3 (on some systems)
+  call signal (10, 1)  ! 10 = SIGUSR1 and 1 = SIG_IGN (on some systems)
 
   call sleep (30)
 end program test_signal