Re^4: Non-blocking Reads from Pipe Filehandle

Replies are listed 'Best First'.
Re^5: ... (Proof!) by BrowserUk (Patriarch) on Oct 01, 2008 at 03:40 UTC
It's definitely a necessity even though though it could be fudged this time. For the record. This is from API.XS: `case T_POINTER: ## If pointer params[i].t = T_POINTER; origST[i] = ST(i+1); if(has_proto) { pointerCallPack(ST(i+1), i, intypes); params[i].p = (char ) SvPV_nolen(ST(i+1)); } else { ## and no proto if(SvIOK(ST(i+1)) && SvIV(ST(i+1)) == 0) { ## and IV is OK +and zero params[i].p = NULL; ## use NULL } else { params[i].p = (char ) SvPV_nolen(ST(i+1)); ## else use th +e address of the PV } }` [download] So, if you work with the module instead of fighting it, and use 0 (zero) instead of undef to indicate that you want this pointer parameter set to null, that's what it does! Ie. it's not a "fudge", but how the author designed it! Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. "Science is about questioning the status quo. Questioning authority". In the absence of evidence, opinion is indistinguishable from prejudice. "Too many [] have been sedated by an oppressive environment of political correctness and risk aversion."	[reply] [d/l]
Re^6: ... (Proof!) by ikegami (Patriarch) on Oct 01, 2008 at 04:00 UTC
I used 0. Didn't work. But then again, `has_proto` is true for the snippet that shows the problem. What's getting you so excited? Update: Bug report. Proposed change: case T_POINTER: params[i].t = T_POINTER; origST[i] = ST(i+1); if(has_proto) { - pointerCallPack(ST(i+1), i, intypes); - params[i].p = (char ) SvPV_nolen(ST(i+1)); + if(SvOK(ST(i+1)) { + pointerCallPack(ST(i+1), i, intypes); + params[i].p = (char ) SvPV_nolen(ST(i+1)); + } else { + params[i].p = NULL; + } } else { if(SvIOK(ST(i+1)) && SvIV(ST(i+1)) == 0) { params[i].p = NULL; } else { params[i].p = (char *) SvPV_nolen(ST(i+1)); } } ... if(params[i].t == T_POINTER && has_proto) { - pointerCallUnpack(origST[i], i, intypes); + if(SvOK(origST[i]) { + pointerCallUnpack(origST[i], i, intypes); + } } [download]	[reply] [d/l] [select]
Re^7: ... (Proof!) by BrowserUk (Patriarch) on Oct 01, 2008 at 04:59 UTC
I used 0. Didn't work. Probably because your protoype is wrong. This: `my $f = Win32::API->new('kernel32', 'PeekNamedPipe', 'LLLLLL', 'L')` Should be this: `my $f = Win32::API->new('kernel32', 'PeekNamedPipe', 'LPLPPP', 'L')` Fix that, and your 'fix' above is unnecessary. Just another hack at a module that worked fine for the most part before people start trying 'fix it' without enough knowledge to do so. I wouldn't call it excitement. More depression when I see people proffering this kind unnecessary complexity: sub get_pv { local $^W; unpack 'L!', pack 'P', $_[0] } BEGIN { # BOOL PeekNamedPipe( # HANDLE hNamedPipe, # LPVOID lpBuffer, # DWORD nBufferSize, # LPDWORD lpBytesRead, # LPDWORD lpTotalBytesAvail, # LPDWORD lpBytesLeftThisMessage # ) my $f = Win32::API->new('kernel32', 'PeekNamedPipe', 'LLLLLL', 'L') or die $^E; sub PeekNamedPipe { my $nBytesRead; my $nTotalBytesAvail; my $nBytesLeftThisMessage; $nBytesRead = pack('L!', $_[3]) if defined $_[3]; $nTotalBytesAvail = pack('L!', $_[4]) if defined $_[4]; $nBytesLeftThisMessage = pack('L!', $_[5]) if defined $_[5]; my $rv = $f->Call( $_[0], get_pv($_[1]), $_[2], get_pv($nBytesRead), get_pv($nTotalBytesAvail), get_pv($nBytesLeftThisMessage), ); $_[3] = unpack('L!', $nBytesRead ) if defined $_[3]; $_[4] = unpack('L!', $nTotalBytesAvail ) if defined $_[4]; $_[5] = unpack('L!', $nBytesLeftThisMessage) if defined $_[5]; return $rv; } } [download] for the sake of a little reading, and a couple of zeros. The icing on the cake is when they try to claim the technical high ground as justifiction for it. Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. "Science is about questioning the status quo. Questioning authority". In the absence of evidence, opinion is indistinguishable from prejudice. "Too many [] have been sedated by an oppressive environment of political correctness and risk aversion."	[reply] [d/l] [select]
Re^8: ... (Proof!) by ikegami (Patriarch) on Oct 01, 2008 at 05:31 UTC
Re^6: ... (Proof!) by ikegami (Patriarch) on Oct 01, 2008 at 06:25 UTC
it's not a "fudge" `lpTotalBytesAvail` and `lpBytesLeftThisMessage` are both `LPDWORD`. You pass zero to both. Yet, you want me to believe doing so results in passing a non-`NULL` pointer for `lpTotalBytesAvail` and a `NULL` pointer for `lpBytesLeftThisMessage`?	[reply] [d/l] [select]
Re^7: ... (Proof!) by BrowserUk (Patriarch) on Oct 01, 2008 at 07:34 UTC
No. Both are passed as NULL-pointers: c:\test>buk-pipe.pl (XS)Win32::API::Call: prototype? 0 [n/a] (XS)Win32::API::Call: params[0].t=1, .u=76 (XS)Win32::API::Call: params[1].t=2, .u= (XS)Win32::API::Call: params[2].t=1, .u=1024 (XS)Win32::API::Call: params[3].t=2, .u=(null) (XS)Win32::API::Call: params[4].t=2, .u=(null) (XS)Win32::API::Call: params[5].t=2, .u=(null) (XS)Win32::API::Call: parameter 5 (P) is (null) (XS)Win32::API::Call: parameter 4 (P) is (null) (XS)Win32::API::Call: parameter 3 (P) is (null) (XS)Win32::API::Call: parameter 2 (N) is 1024 (XS)Win32::API::Call: parameter 1 (P) is (XS)Win32::API::Call: parameter 0 (N) is 76 (XS)Win32::API::Call: Calling ApiFunctionInteger() (XS)Win32::API::Call: ApiFunctionInteger returned 1 (XS)Win32::API::Call: freeing memory... (XS)Win32::API::Call: returning to caller. (XS)Win32::API::Call: returning 1. ... [download] If you look closely, you'll see that I am not actually using `lpTotalBytesAvail` / `$cAvail`. I was in an early cut of the code, but then I realised that I didn't need to. It is easier to extract the information I need directly from the buffer. When I was using `$cAvail`, it was coded like to this: `sub readlineMaybe { my $fh = shift; my $osfh = GetOsFHandle( $fh ) or die $^E; my( $bufsize, $buffer, $cAvail, $read ) = ( 1024, chr(0)x1024, chr +(0)x4, 0 ); PeekNamedPipe( $osfh, $buffer, $bufsize, $read, $cAvail, 0 ) or $^E == 109 or die $^E; print 'Available: ', unpack 'V', $cAvail; return if $^E == 109; my $eolPos = 1+index $buffer, $/; return '' unless $eolPos; sysread( $fh, $buffer, $eolPos ) or die $!; return $buffer; }` [download] Which produces this output: c:\test>buk-pipe.pl (XS)Win32::API::Call: prototype? 0 [n/a] (XS)Win32::API::Call: params[0].t=1, .u=76 (XS)Win32::API::Call: params[1].t=2, .u= (XS)Win32::API::Call: params[2].t=1, .u=1024 (XS)Win32::API::Call: params[3].t=2, .u=(null) (XS)Win32::API::Call: params[4].t=2, .u= (XS)Win32::API::Call: params[5].t=2, .u=(null) (XS)Win32::API::Call: parameter 5 (P) is (null) (XS)Win32::API::Call: parameter 4 (P) is (XS)Win32::API::Call: parameter 3 (P) is (null) (XS)Win32::API::Call: parameter 2 (N) is 1024 (XS)Win32::API::Call: parameter 1 (P) is (XS)Win32::API::Call: parameter 0 (N) is 76 (XS)Win32::API::Call: Calling ApiFunctionInteger() (XS)Win32::API::Call: ApiFunctionInteger returned 1 (XS)Win32::API::Call: freeing memory... (XS)Win32::API::Call: returning to caller. (XS)Win32::API::Call: returning 1. Available: 0 (XS)Win32::API::Call: prototype? 0 [n/a] (XS)Win32::API::Call: params[0].t=1, .u=76 (XS)Win32::API::Call: params[1].t=2, .u= (XS)Win32::API::Call: params[2].t=1, .u=1024 (XS)Win32::API::Call: params[3].t=2, .u=(null) (XS)Win32::API::Call: params[4].t=2, .u= (XS)Win32::API::Call: params[5].t=2, .u=(null) (XS)Win32::API::Call: parameter 5 (P) is (null) (XS)Win32::API::Call: parameter 4 (P) is (XS)Win32::API::Call: parameter 3 (P) is (null) (XS)Win32::API::Call: parameter 2 (N) is 1024 (XS)Win32::API::Call: parameter 1 (P) is (XS)Win32::API::Call: parameter 0 (N) is 76 (XS)Win32::API::Call: Calling ApiFunctionInteger() (XS)Win32::API::Call: ApiFunctionInteger returned 1 (XS)Win32::API::Call: freeing memory... (XS)Win32::API::Call: returning to caller. (XS)Win32::API::Call: returning 1. Available: 37 Got: 'Wed Oct 1 08:32:59 2008: some text' ... [download] Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. "Science is about questioning the status quo. Questioning authority". In the absence of evidence, opinion is indistinguishable from prejudice. "Too many [] have been sedated by an oppressive environment of political correctness and risk aversion."	[reply] [d/l] [select]
Re^5:Non-blocking Reads from Pipe Filehandle by BrowserUk (Patriarch) on Oct 01, 2008 at 02:31 UTC
It stopped your program from working for over a year. It's forcing you to have to OS do unnecessary and possible unwanted work. It's definitely a necessity even though though it could be fudged this time. Oh dear. You really do talk bollocks sometimes! My "program" was a throw away attempt at something to which I already had (and posted) a simpler, better alternative. What stopped that throw-away from working, for the whole 10 minutes I spent on it, had absolutely nothing to do with all your ballshit above about "having to manage your own buffers". As I demonstrated, that is all completely unnecessary. You (and your mentor) just like doing things the hard way for some reason. Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. "Science is about questioning the status quo. Questioning authority". In the absence of evidence, opinion is indistinguishable from prejudice. "Too many [] have been sedated by an oppressive environment of political correctness and risk aversion."	[reply]