axf-os161 / man / testbin / usemtest.html
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<title>usemtest</title>
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<h2 align=center>usemtest</h2>
<h4 align=center>OS/161 Reference Manual</h4>

<h3>Name</h3>
<p>
usemtest - test semfs (<tt>sem:</tt>) semaphores
</p>

<h3>Synopsis</h3>
<p>
<tt>/testbin/usemtest</tt>
</p>

<h3>Description</h3>
<p>
<tt>usemtest</tt> forks some subprocesses and uses the semfs
semaphores to do coordinated printing. It is somewhat similar to the
<tt>sy1</tt> in-kernel test for the in-kernel semaphores.
</p>

<p>
The first parts of the test open each semaphore separately in each
process, so locking issues in the filetable and open-file code should
not keep it from running.
The last part opens the semaphores once and inherits the file
descriptors through fork; it is likely to hang (including sometimes in
fork) if the filetable and open-file locking is not just so.
</p>

<h3>Requirements</h3>
<p>
<tt>usemtest</tt> uses the following system calls:
<ul>
<li> <A HREF=../syscall/fork.html>fork</A>
<li> <A HREF=../syscall/open.html>open</A>
<li> <A HREF=../syscall/read.html>read</A>
<li> <A HREF=../syscall/read.html>remove</A>
<li> <A HREF=../syscall/waitpid.html>waitpid</A>
<li> <A HREF=../syscall/write.html>write</A>
<li> <A HREF=../syscall/_exit.html>_exit</A>
</ul>
</p>

<p>
<tt>usemtest</tt> should run successfully once the basic system calls
are complete.
Until you implement the <tt>remove()</tt> system call the semaphores
from the test will be left lying around afterwards, but this should
not keep it from running.
</p>

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