<HTML><BODY style="word-wrap: break-word; -khtml-nbsp-mode: space; -khtml-line-break: after-white-space; ">hey tim,<DIV><BR class="khtml-block-placeholder"></DIV><DIV>...as you can see, I posted to a "unix-porting" list at apple, and got this neat-o response: so whatcha think? Not as portable as once thought, I'd imagine...I'd guess it also wouldn't work on other bsd's, but then, is anyone running pd on a *bsd?<BR><DIV><BR class="khtml-block-placeholder"></DIV><DIV>...back to the drawing board for me...</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV>l8r,</DIV><DIV>jamie</DIV><DIV><BR><DIV>Begin forwarded message:</DIV><BR class="Apple-interchange-newline"><BLOCKQUOTE type="cite"><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><FONT face="Helvetica" size="3" color="#000000" style="font: 12.0px Helvetica; color: #000000"><B>From: </B></FONT><FONT face="Helvetica" size="3" style="font: 12.0px Helvetica">Terry Lambert <<A href="mailto:tlambert@apple.com">tlambert@apple.com</A>></FONT></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><FONT face="Helvetica" size="3" color="#000000" style="font: 12.0px Helvetica; color: #000000"><B>Date: </B></FONT><FONT face="Helvetica" size="3" style="font: 12.0px Helvetica">July 12, 2005 10:57:16 PM EDT</FONT></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><FONT face="Helvetica" size="3" color="#000000" style="font: 12.0px Helvetica; color: #000000"><B>To: </B></FONT><FONT face="Helvetica" size="3" style="font: 12.0px Helvetica">james tittle <<A href="mailto:tigital@mac.com">tigital@mac.com</A>></FONT></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><FONT face="Helvetica" size="3" color="#000000" style="font: 12.0px Helvetica; color: #000000"><B>Cc: </B></FONT><FONT face="Helvetica" size="3" style="font: 12.0px Helvetica"><A href="mailto:unix-porting@lists.apple.com">unix-porting@lists.apple.com</A></FONT></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><FONT face="Helvetica" size="3" color="#000000" style="font: 12.0px Helvetica; color: #000000"><B>Subject: </B></FONT><FONT face="Helvetica" size="3" style="font: 12.0px Helvetica"><B>Re: sched_setscheduler(), posix and 10.4.x?</B></FONT></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV> <BR class="Apple-interchange-newline"><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">On Jul 12, 2005, at 5:47 PM, james tittle wrote:</DIV> <BR><BLOCKQUOTE type="cite"><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">hi,</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">...I'm working on a crossplatform app in which someone has implemented sched_setscheduler(), and apparently it's not available on 10.4.x?<SPAN class="Apple-converted-space"> </SPAN>I've tried compiling against the 10.4.0.sdk using:</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">gcc -framework CoreAudio -framework AudioUnit -framework AudioToolbox -framework Carbon -framework CoreMIDI -isysroot /Developer/SDKs/MacOSX10.4.0.sdk -Wl,-syslibroot,/Developer/SDKs/MacOSX10.4.0.sdk -O3 -fprefetch-loop-arrays -faltivec -maltivec -isysroot /Developer/SDKs/MacOSX10.4.0.sdk (...snipped lotsa filenames...)</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">...but still no luck...this seems to violate the POSIX standard, because unistd.h does define _POSIX_PRIORITY_SCHEDULING, whereas "POSIX systems on which sched_setscheduler and sched_getscheduler are available define _POSIX_PRIORITY_SCHEDULING in <unistd.h>."</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">help?</DIV> <BR></BLOCKQUOTE><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">The code you're trying to compile is not technically portable; the value (-1) means "unsupported" according to the current POSIX standards document.<SPAN class="Apple-converted-space"> </SPAN>You will tend to have problems porting it to other POSIX or POSIX-like platforms, not just MacOS X.</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">This is an increasingly common mistake that pops up now due to a change between POSIX<SPAN class="Apple-converted-space"> </SPAN>1003.1-2001 and POSIX 1003.1-2003, which requires that these values be defined in all cases, but have particular values based on whether or not the option is supported (-1 means "unsupported"; 0 also means "unsupported", and is included because if the value is not #defined at all, and you do math with it, the ISO c99 standard requires a preprocess treat the value as if it were zero; 200112L means "supported").</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">That means that the feature test in C programs has to change from:</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> </SPAN>#ifdef _POSIX_PRIORITY_SCHEDULING</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">to:</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> </SPAN>#if (_POSIX_PRIORITY_SCHEDULING - 0) >=<SPAN class="Apple-converted-space"> </SPAN>200112L</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Which is what it really should have been all along.<SPAN class="Apple-converted-space"> </SPAN>Technically, it could also be:</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> </SPAN>#if defined(_POSIX_PRIORITY_SCHEDULING) && (_POSIX_PRIORITY_SCHEDULING == 200112L)</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">But if you used that variant, your code would not be future-proof against newer versions of the standard bumping the constant from 200112L to something larger (obviously, they could also change the semantics if they did that, but you at least have a fighting chance of your code still working without additional changes).</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">See also:</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> </SPAN><A href="http://www.opengroup.org/onlinepubs/009695399/basedefs/unistd.h.html">http://www.opengroup.org/onlinepubs/009695399/basedefs/unistd.h.html</A></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> </SPAN>"If a symbolic constant is defined with the value -1, the option is</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> </SPAN>not supported. Headers, data types, and function interfaces required</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> </SPAN>only for the option need not be supplied. An application that attempts</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> </SPAN>to use anything associated only with the option is considered to be</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> </SPAN>requiring an extension."</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> </SPAN>[ ... ]</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> </SPAN>"_POSIX_PRIORITY_SCHEDULING The implementation supports the Process</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> </SPAN>Scheduling option.<SPAN class="Apple-converted-space"> </SPAN>If this symbol is defined in <unistd.h>, it shall</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> </SPAN>be defined to be -1, 0, or 200112L. The value of this symbol reported</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><SPAN class="Apple-converted-space"> </SPAN>by sysconf() shall either be -1 or 200112L."</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">Hope that clears things up for you!</DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><BR></DIV><DIV style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; ">-- Terry</DIV> <BR class="Apple-interchange-newline"></BLOCKQUOTE></DIV><BR></DIV></BODY></HTML>