Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 6/24/83; site utah-gr.UUCP Path: utzoo!watmath!clyde!burl!ulysses!allegra!mit-eddie!genrad!panda!talcott!harvard!seismo!utah-cs!utah-gr!thomas From: thomas@utah-gr.UUCP (Spencer W. Thomas) Newsgroups: net.unix-wizards Subject: Re: SHMOP (SYSV) Message-ID: <1619@utah-gr.UUCP> Date: Sat, 2-Nov-85 17:25:46 EST Article-I.D.: utah-gr.1619 Posted: Sat Nov 2 17:25:46 1985 Date-Received: Mon, 4-Nov-85 03:15:44 EST References: <132000020@hpfcls.UUCP> Reply-To: thomas@utah-gr.UUCP (Spencer W. Thomas) Organization: Univ of Utah CS Dept Lines: 16 In article <132000020@hpfcls.UUCP> rml@hpfcla.UUCP writes: >From the way most UN*X implementations (including the early ones) have >been written, *all* system calls return -1 on failure. Hoo boy! Gotcha on this one. Both the PDP-11(V6/V7) and VAX(32V-4.3bsd) versions of Unix set the CARRY BIT to indicate error. The actual error code is returned in r0. Returning -1 for error is a C LANGUAGE convention (since it's hard to test the carry bit in C). Granted, the routine "cerror" always returns -1 on an error. This is a bitch when the system call can legitimately return -1. -- =Spencer ({ihnp4,decvax}!utah-cs!thomas, thomas@utah-cs.ARPA) "When wrath runs rampage in your heart you must hold still that rambunctions tongue!" - Sappho