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digitalmars.D.learn - Shutdown signals

reply Tim <tim.oliver tutanota.com> writes:
Hi all,

How can I get a D program to detect something a keyboard 
interrupt so I shut things down in a specific way?
May 10 2021
parent reply Adam D. Ruppe <destructionator gmail.com> writes:
On Monday, 10 May 2021 at 23:20:47 UTC, Tim wrote:

 Hi all,

 How can I get a D program to detect something a keyboard 
 interrupt so I shut things down in a specific way?


import core.sys.posix.signal; then you can use the same functions 
as C to set signal handlers.
May 10 2021
parent reply Tim <tim.oliver tutanota.com> writes:
On Monday, 10 May 2021 at 23:31:11 UTC, Adam D. Ruppe wrote:

 On Monday, 10 May 2021 at 23:20:47 UTC, Tim wrote:

 Hi all,

 How can I get a D program to detect something a keyboard 
 interrupt so I shut things down in a specific way?


 import core.sys.posix.signal; then you can use the same 
 functions as C to set signal handlers.


I can't find that in the docs, nor in dpldocs. Can you help out 
with this?
May 10 2021
parent reply Adam D. Ruppe <destructionator gmail.com> writes:
On Monday, 10 May 2021 at 23:35:06 UTC, Tim wrote:

 I can't find that in the docs, nor in dpldocs. Can you help out 
 with this?


dpldocs.info/signal it comes up as the second result.

The C function you call from there (on linux anyway) is 
sigaction. A little copy/paste out of my terminal.d:

```d
       // I check this flag in my loop to see if an interruption 
happened
       // then i can cleanly exit from there.
        __gshared bool interrupted;

       // the interrupt handler just sets the flag
        extern(C)
        void interruptSignalHandler(int sigNumber) nothrow {
                interrupted = true;
        }

        // then this code registers the handler with the system
        import core.sys.posix.signal;
        sigaction_t n;
        n.sa_handler = &interruptSignalHandler;
        sigaction(SIGINT, &n, &oldSigIntr); // third arg can also 
be null if you don't care about the old one
```
May 10 2021
parent reply Tim <tim.oliver tutanota.com> writes:
On Monday, 10 May 2021 at 23:55:18 UTC, Adam D. Ruppe wrote:

 On Monday, 10 May 2021 at 23:35:06 UTC, Tim wrote:

 [...]


 dpldocs.info/signal it comes up as the second result.

 The C function you call from there (on linux anyway) is 
 sigaction. A little copy/paste out of my terminal.d:

 ```d
       // I check this flag in my loop to see if an interruption 
 happened
       // then i can cleanly exit from there.
        __gshared bool interrupted;

       // the interrupt handler just sets the flag
        extern(C)
        void interruptSignalHandler(int sigNumber) nothrow {
                interrupted = true;
        }

        // then this code registers the handler with the system
        import core.sys.posix.signal;
        sigaction_t n;
        n.sa_handler = &interruptSignalHandler;
        sigaction(SIGINT, &n, &oldSigIntr); // third arg can 
 also be null if you don't care about the old one
 ```


I don't know why I didn't find that. I was searching for the full 
name, maybe too specific? Thanks anyways, this is super helpful. 
I wish it was documented better though :(

So why use sigaction and not signal? From what I can tell signal 
is the C way of doing things
May 10 2021
parent reply Patrick Schluter <Patrick.Schluter bbox.fr> writes:
On Tuesday, 11 May 2021 at 06:44:57 UTC, Tim wrote:

 On Monday, 10 May 2021 at 23:55:18 UTC, Adam D. Ruppe wrote:

 [...]


 I don't know why I didn't find that. I was searching for the 
 full name, maybe too specific? Thanks anyways, this is super 
 helpful. I wish it was documented better though :(

 So why use sigaction and not signal? From what I can tell 
 signal is the C way of doing things


Use `sigaction()`, `signal()` has problems. See this 
stackoverflow [1] question explains the details

[1]: 
https://stackoverflow.com/questions/231912/what-is-the-difference-between-sigaction-and-signal
May 10 2021
parent Tim <tim.oliver tutanota.com> writes:
On Tuesday, 11 May 2021 at 06:59:10 UTC, Patrick Schluter wrote:

 On Tuesday, 11 May 2021 at 06:44:57 UTC, Tim wrote:

 On Monday, 10 May 2021 at 23:55:18 UTC, Adam D. Ruppe wrote:

 [...]


 I don't know why I didn't find that. I was searching for the 
 full name, maybe too specific? Thanks anyways, this is super 
 helpful. I wish it was documented better though :(

 So why use sigaction and not signal? From what I can tell 
 signal is the C way of doing things


 Use `sigaction()`, `signal()` has problems. See this 
 stackoverflow [1] question explains the details

 [1]: 
 https://stackoverflow.com/questions/231912/what-is-the-difference-between-sigaction-and-signal


Thanks a lot!
May 11 2021