Global signals

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This article, originally made by SplinterGU, tries to explain how to do a signal to all process and how to recover the initial state of all affected processes.

Here there are the code of the two functions needed to do it.

import "mod_proc";

/* ---------------------------------- */

#define S_FORCE             50
#define S_TREE              100

/* ---------------------------------- */

local
    saved_status ;
end

/* ---------------------------------- */

function save_state_and_signal( int pid, int sig )
begin
    if ( sig >= S_TREE )
        sig -= S_TREE;
    end

    if ( sig >= S_FORCE )
        sig -= S_FORCE;
    end

    if ( !pid )
        while ( pid = get_id(ALL_PROCESS) )
            if ( pid != id && pid != father )
                pid.saved_status = get_status( pid );
                signal( pid, S_FORCE + sig );
            end
        end
    else
        if ( pid != father )
            pid.saved_status = get_status( pid );
            signal( pid, S_FORCE + sig );
        end
    end
end

/* ---------------------------------- */

function restore_state( int pid )
begin
    if ( !pid )
        while ( pid = get_id(ALL_PROCESS) )
            if ( pid != id && pid != father )
                signal( pid, S_FORCE + pid.saved_status );
            end
        end
    else
        if ( pid != father )
            signal( pid, S_FORCE + pid.saved_status );
        end
    end
end

/* ---------------------------------- */

You can add it to your main ".prg" code or make a file named "global_signal.prg" and add a include line to it in your code.

Here is an example of how to call they:

save_state_and_signal( 0 , s_freeze );      // Freezes all processes.
restore_state(0);  // restore all processes

You can use it like signal function that saves the original state of the process, too.