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<concept id="GUID-B58D282E-E6EC-4AE1-96DB-30A5FB850563" xml:lang="en"><title><codeph>exec()</codeph> without
forking using <apiname>posix_spawn()</apiname></title><prolog><metadata><keywords/></metadata></prolog><conbody>
<p>A UNIX® program may exec without forking. The result is that the calling
process executes another binary, but inherits certain properties, for example,
file descriptors.  </p>
<p>The P.I.P.S. equivalent would be to call <xref href="GUID-E7C4DE71-BC5B-34AE-ACB3-C34A0DB1FC16.dita"><apiname>posix_spawn()</apiname></xref> and
pass any inherited data via <codeph>argv</codeph> parameters.  </p>
<p>Note that if a parent process is waiting for the child to terminate then
the termination of the newly created task must be synchronised. Therefore
a <xref href="GUID-8F5C89A4-7813-32C7-973E-F7F0F3690BC6.dita"><apiname>waitpid()</apiname></xref> call should follow the <xref href="GUID-E7C4DE71-BC5B-34AE-ACB3-C34A0DB1FC16.dita"><apiname>posix_spawn()</apiname></xref> call
so that it does not exit prematurely. Otherwise <xref href="GUID-FED685F4-5FAD-39F4-9812-3B0A85D8718C.dita"><apiname>exit()</apiname></xref> can
be called after the posix_spawn().  </p>
<p>Also, note that if the process which formerly executed and
which now uses <xref href="GUID-E7C4DE71-BC5B-34AE-ACB3-C34A0DB1FC16.dita"><apiname>posix_spawn()</apiname></xref> stores its PID (for example,
in the file system) to allow other processes to target it, then care must
be taken to store the relevant PID (Process ID). This is because the PID for
the newly spawned process may need to be stored instead.</p>
</conbody></concept>