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<title>system</title>
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<h2 align=center>system</h2>
<h4 align=center>OS/161 Reference Manual</h4>

<h3>Name</h3>
system - run command as subprocess

<h3>Library</h3>
Standard C Library (libc, -lc)

<h3>Synopsis</h3>
#include &lt;stdlib.h&gt;<br>
<br>
int<br>
system(const char *<em>command</em>);

<h3>Description</h3>

The system routine executes <em>command</em> as if it were typed into
the shell.

<h3>Return Values</h3>
On success, system returns the exit status returned from 
<A HREF=../syscall/waitpid.html>waitpid</A>. 
On error, -1 is returned, and <A HREF=../syscall/errno.html>errno</A> 
is set according to the error encountered.

<h3>Errors</h3>

Any of the errors from <A HREF=../syscall/fork.html>fork</A> or
<A HREF=../syscall/waitpid.html>waitpid</A>. Errors generated during
<A HREF=../syscall/execv.html>execv</A> cannot readily be reported
back in detail.

<h3>Restrictions</h3>

In OS/161 there may be no shell and when there is the shell's behavior
and syntax is not specified. For this reason we make no assumptions
about the shell's operation, and assume system() cannot reliably use
the shell to parse and execute <em>command</em>. system() does this
itself, in a way which may not necessarily be compatible with the
shell as it finally appears. You may want to change system() to invoke
the shell in a suitable fashion when/if a shell is available.

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