using signals instead of busy wait Post: 302146519

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Top Forums Programming using signals instead of busy wait Post 302146519 by porter on Wednesday 21st of November 2007 02:48:25 AM

11-21-2007

Registered User

Quote:

Originally Posted by jut26

I am looking for some examples of c programs which use a signal to notify the program to begin a certain action instead of having it continually loop to check to see if condition is attained

I suggest a program based around select and have a pipe pair dedicated to supporting signals. The write end is written by the signal handle (write a single byte containing the number of the signal) and have the select include the read end of the pipe in the read fd_set.

Then when a signal occurs a single byte is written to the pipe, this wakes up the select, the code in the select loop then reads the pipe and knows which signal occurred and can then handle it in a more graceful manner.

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LEARN ABOUT SUNOS

select

select.h(3HEAD) 						      Headers							   select.h(3HEAD)

NAME

       select.h, select - select types

SYNOPSIS

       #include <sys/select.h>

DESCRIPTION

       The <sys/select.h> header defines the timeval structure, which includes the following members:

       time_t	   tv_sec      /* seconds */
       suseconds_t tv_usec     /* microseconds */

       The time_t and suseconds_t types are defined as described in <sys/types.h>. See types.h(3HEAD).

       The sigset_t type is defined as described in signal.h(3HEAD).

       The timespec structure is defined as described in <time.h>. See time.h(3HEAD).

       The <sys/select.h> header defines the fd_set type as a structure.

       The following is defined as a macro:

       FD_SETSIZE      Maximum number of file descriptors in an fd_set structure.

       Inclusion of the <sys/select.h> header can make visible all symbols from the headers <signal.h>, <sys/time.h>, and <time.h>.

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Standard			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       select(3C), signal.h(3HEAD), time.h(3HEAD), types.h(3HEAD), attributes(5), standards(5)

SunOS 5.10							    10 Sep 2004 						   select.h(3HEAD)