Received: from snow-white.ee.udel.edu by whimsy.udel.edu id aa22801; 11 Mar 97 20:23 GMT Received: by carbon.chem.nyu.edu (SMI-8.6/1.20) id PAA29481; Tue, 11 Mar 1997 15:19:08 -0500 Date: Tue, 11 Mar 1997 15:19:08 -0500 Message-Id: <199703112019.PAA29481@carbon.chem.nyu.edu> From: "Edward J. Huff" To: Mills@huey.udel.edu CC: Mills@huey.udel.edu, stenn@whimsy.udel.edu, Mills@huey.udel.edu, Don.Lewis@tsc.tdk.com, WhiskerP@logica.com In-reply-to: <9703111439.aa06819@huey.udel.edu> (Mills@huey.udel.edu) Subject: Re: Adding volatile to variables shared with signal handlers >Thanks for the alert. I suspect we have not heard the last of this >issue. I said "volatile required for variabled modified by signal handler." Actually, it is possible to construct a case where volatile would be required to force the compiler to actually store the values specified into the static variables in the mainline routine so that the signal handler will read the correct value. So I suppose strictly speaking the variables which are read by the signal handler should also be marked volatile. activefds INPUT ONLY maxactivefd INPUT ONLY refio INPUT ONLY ninterfaces INPUT ONLY debug INPUT ONLY Actually, the book says "You specify volatile qualified types for objects accessed or altered by signal handlers, by concurrently executing programs, or by special hardware (such as memory-mapped I/O control register)." Also "A volatile qualified type indicates that agencies unknown to the translator can access or alter the value stored in the object. The translator can assume that it has complete control of all objects that do not have volatile qualified types."