Signal Handler .sa_mask

I'm trying to set up a signal handler so that I can catch catch SIGIO to handle async read operations from the serial port. I define my signal handler as:

Code:

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void signal_handler_IO (int status);

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and then define the signal action:

Code:

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struct sigaction saio;

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then to put it all together I got this from tldp:

Code:

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        /* install the signal handler before making the device asynchronous */
        saio.sa_handler = signal_handler_IO;
        saio.sa_mask = 0;
        saio.sa_flags = 0;
        saio.sa_restorer = NULL;
        sigaction(SIGIO,&saio,NULL);
         
        /* allow the process to receive SIGIO */
        fcntl(fd, F_SETOWN, getpid());
        /* Make the file descriptor asynchronous (the manual page says only
          O_APPEND and O_NONBLOCK, will work with F_SETFL...) */
        fcntl(fd, F_SETFL, FASYNC);

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the problem is when I compile I recieve an error "no match for `__sigset_t & = int'" on the line "saio.sa_mask = 0;". I've tried putting signals that I know to be valid in this space and even typecasting to sigset_t but the problem persists. Is there something I'm overlooking here?

I'm using GCC version 2.95.4 on debian linux

thanks,
Devan