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Full Discussion: How many semaphores?
Top Forums UNIX for Advanced & Expert Users How many semaphores? Post 302144305 by kahuna on Wednesday 7th of November 2007 08:20:54 AM
Old 11-07-2007
Is the requirement that only semaphores be used? It seems to me that all it would take is single semaphore that guards access to a memory location that indicates the last process completed. Each process would wait on the semaphore and once it got access, would check to see if its predecessor had run. If so it would execute and update the last process completed. If not, it would release the semaphore and try again.
 

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LEARN ABOUT SUNOS

semaphore.h

semaphore.h(3HEAD)						      Headers							semaphore.h(3HEAD)

NAME

       semaphore.h, semaphore - semaphores

SYNOPSIS

       #include <semaphore.h>

DESCRIPTION

       The  <semaphore.h>  header  defines  the sem_t type, used in performing semaphore operations. The semaphore can be implemented using a file
       descriptor, in which case applications are able to open up at least a total of {OPEN_MAX} files and semaphores. The  symbol  SEM_FAILED	is
       defined (see sem_open(3RT)).

       Inclusion  of  the <semaphore.h> header can make visible symbols defined in the headers <fcntl.h> and <sys/types.h>. See fcntl.h(3HEAD) and
       types.h(3HEAD).

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Standard			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       fcntl.h(3HEAD), types.h(3HEAD),	sem_destroy(3RT),  sem_getvalue(3RT),  sem_init(3RT),  sem_open(3RT),  sem_post(3RT),  sem_timedwait(3RT),
       sem_unlink(3RT), sem_wait(3RT), attributes(5), standards(5)

SunOS 5.10							    10 Sep 2004 						semaphore.h(3HEAD)
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