[Linux]Linux下signal function傳參方式

https://stackoverflow.com/questions/6970224/providing-passing-argument-to-signal-handler

 

This is a really old question but I think I can show you a nice trick that would have answered your problem. No need to use sigqueue or whatever.

I also dislike the use of globals variables so I had to find a clever way, in my case, to send a void ptr (which you can later cast to whatever suits your need).

Actually you can do this :

signal(SIGWHATEVER, (void (*)(int))sighandler); // Yes it works ! Even with -Wall -Wextra -Werror using gcc

Then your sighandler would look like this :

int sighandler(const int signal, void *ptr) // Actually void can be replaced with anything you want , MAGIC !

You might ask : How to get the *ptr then ?

Here's how : At initialization

signal(SIGWHATEVER, (void (*)(int))sighandler) sighandler(FAKE_SIGNAL, your_ptr);

In your sighandler func :

int sighandler(const int signal, void *ptr) { static my_struct saved = NULL; if (saved == NULL) saved = ptr; if (signal == SIGNALWHATEVER) // DO YOUR STUFF OR FREE YOUR PTR return (0); }