• Norbert Preining (65/65) Dec 25 2018 Hello everyone,
• Basile B (6/32) Dec 26 2018 The technique to use here is to wrap the non-gc code in a

Norbert Preining <norbert preining.info> writes:

Hello everyone,
we are writing a program that synchronizes the OneDrive cloud 
service with the local computer, and run it as daemon in the 
background. To ensure proper database shutdown on exit, we need 
to install signal handlers that react to SIGINT etc.

The problem now is that at the same time we use 
std.net.curl.Curl, and that has some kind of bug in the shutdown 
routine when it is called during program termination. One always 
needs to manually call .shutdown, otherwise the program dumps 
core:
```
(gdb) bt


    from /usr/lib/x86_64-linux-gnu/libphobos2-ldc-shared.so.82

_D6object__T7destroyTS3std3net4curl4HTTP4ImplZQBiFKQBeZv ()
    from /usr/lib/x86_64-linux-gnu/libphobos2-ldc-shared.so.82

_D3std8typecons__T10RefCountedTSQBe3net4curl4HTTP4ImplVEQCcQCb24RefCountedAutoInitial
zei1ZQCv6__dtorMFZv () from
/usr/lib/x86_64-linux-gnu/libphobos2-ldc-shared.so.82

/usr/lib/x86_64-linux-gnu/libdruntime-ldc-shared.so.82

_D2gc4impl12conservativeQw15SmallObjectPool13runFinalizersMFNbxAvZv ()
    from /usr/lib/x86_64-linux-gnu/libdruntime-ldc-shared.so.82

_D2gc4impl12conservativeQw3Gcx13runFinalizersMFNbxAvZv ()
    from /usr/lib/x86_64-linux-gnu/libdruntime-ldc-shared.so.82

_D2gc4impl12conservativeQw14ConservativeGC__T9runLockedS_DQCeQCeQCcQCnQBs13runFinalizersMFNbxAvZ2goFNbPSQDyQDyQDwQEh3GcxxQBcZvS_DQExQExQEvQFg9otherTimelS_DQFxQFxQFvQGg9numOtherslTQCzTxQD
ZQFnMFNbKQDqKxQEeZv ()
    from /usr/lib/x86_64-linux-gnu/libdruntime-ldc-shared.so.82

_DThn16_2gc4impl12conservativeQw14ConservativeGC13runFinalizersMFNbxAvZv ()
    from /usr/lib/x86_64-linux-gnu/libdruntime-ldc-shared.so.82

/usr/lib/x86_64-linux-gnu/libdruntime-ldc-shared.so.82



listp=0x7faf589ff718 <__exit_funcs>,
     run_list_atexit=run_list_atexit entry=true, 
run_dtors=run_dtors entry=true) at exit.c:108

exit.c:139

```
Now, unfortunately the call to the shutdown procedure is not 
possible in ` nogc`, so I am a bit at loss how to deal with all 
this.

The code I am using is:
```
extern(C)  nogc  system void exitHandler(int value) {
        printf("Ooohhhh got %d\n", value);
        // workaround for segfault in std.net.curl.Curl.shutdown() 
on exit
        oneDrive.http.shutdown();
        exit(0);
}
```
and in `main` before entering the loop:
```
signal(SIGINT, &exitHandler);
```

Any suggestion would be very much appreciated.

Norbert

Basile B <b2.temp gmx.com> writes:

On Wednesday, 26 December 2018 at 03:19:45 UTC, Norbert Preining 
wrote:
 Hello everyone,
 we are writing a program that synchronizes the OneDrive cloud 
 service with the local computer, and run it as daemon in the 
 background. To ensure proper database shutdown on exit, we need 
 to install signal handlers that react to SIGINT etc.

 [...]
 
 Now, unfortunately the call to the shutdown procedure is not 
 possible in ` nogc`, so I am a bit at loss how to deal with all 
 this.

 The code I am using is:
 ```
 extern(C)  nogc  system void exitHandler(int value) {
        printf("Ooohhhh got %d\n", value);
        // workaround for segfault in 
 std.net.curl.Curl.shutdown() on exit
        oneDrive.http.shutdown();
        exit(0);
 }
 ```
 and in `main` before entering the loop:
 ```
 signal(SIGINT, &exitHandler);
 ```

 Any suggestion would be very much appreciated.

 Norbert

The technique to use here is to wrap the non-gc code in a 
delegate, cast it as a  nogc delegate and call it, see [1] for 
more details.

[1] https://p0nce.github.io/d-idioms/#Bypassing- nogc