Bounded Buffer is hanging, tried all I can. (C++) Post: 302733461

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Homework and Emergencies Homework & Coursework Questions Bounded Buffer is hanging, tried all I can. (C++) Post 302733461 by jim mcnamara on Tuesday 20th of November 2012 02:06:28 PM

11-20-2012

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Quote:

Although, I'm still not clear why this should work if I have more than 5 threads of each going. That would leave the extras in limbo or something?)

The simplest model is with a mutex - like pthread_mutex_t
pseudo code

Code:

// DO NOT dawdle here just read and get the heck out of the mutex
trylock - if busy do something else or loop back so get back into the wait queue
// now you have the mutex
rc= read ()
unlock mutex
// now you do not have the mutex
check return code for < 0 handle error
return number of bytes read or recv() 'd

Do the exact same thing with write or send. Only keep the mutex during the read or write. Do nothing else when you own the mutex.

This model is fine for the situation where you have some processing to do with data, and you read/write and process using threads. I/O is always slower than other operations.

If you have almost no processing to do then threads are not going to gain you much if anything. Your app will always be I/O bound whether it is threaded or not. The idea with threads is to do data crunching or whatever in parallel. When parallelism gains you nothing, skip threading. So if you are misusing threading, then other threads are in fact superfluous.

To avoid hanging on pthread_join, make the threads not joinable, when they return or call

Code:

pthread_exit(NULL)

they simply go away.

jim mcnamara

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LEARN ABOUT REDHAT

glstencilmask

GLSTENCILMASK(3G)														 GLSTENCILMASK(3G)

NAME

       glStencilMask - control the writing of individual bits in the stencil planes

C SPECIFICATION

       void glStencilMask( GLuint mask )

PARAMETERS

       mask  Specifies a bit mask to enable and disable writing of individual bits in the stencil planes.  Initially, the mask is all 1's.

DESCRIPTION

       glStencilMask  controls	the writing of individual bits in the stencil planes.  The least significant n bits of mask, where n is the number
       of bits in the stencil buffer, specify a mask.  Where a 1 appears in the mask, it's possible to write to the corresponding bit in the sten-
       cil buffer.  Where a 0 appears, the corresponding bit is write-protected.  Initially, all bits are enabled for writing.

ERRORS

       GL_INVALID_OPERATION is generated if glStencilMask is executed between the execution of glBegin and the corresponding execution of glEnd.

ASSOCIATED GETS

       glGet with argument GL_STENCIL_WRITEMASK
       glGet with argument GL_STENCIL_BITS

SEE ALSO

       glColorMask(3G), glDepthMask(3G), glIndexMask(3G), glStencilFunc(3G), glStencilOp(3G)

																 GLSTENCILMASK(3G)

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