Issue #16595: Add prlimit() to resource module
prlimit() is a Linux specific command that combines setrlimit, getrlimit and can set the limit
of other processes.
diff --git a/Doc/library/resource.rst b/Doc/library/resource.rst
index 1c0fa9f..d49e13c 100644
--- a/Doc/library/resource.rst
+++ b/Doc/library/resource.rst
@@ -74,6 +74,27 @@
    ``setrlimit`` may also raise :exc:`error` if the underlying system call
    fails.
 
+.. function:: prlimit(pid, resource[, limits])
+
+   Combines :func:`setrlimit` and :func:`getrlimit` in one function and
+   supports to get and set the resources limits of an arbitrary process. If
+   *pid* is 0, then the call applies to the current process. *resource* and
+   *limits* have the same meaning as in :func:`setrlimit`, except that
+   *limits* is optional.
+
+   When *limits* is not given the function returns the *resource* limit of the
+   process *pid*. When *limits* is given the *resource* limit of the process is
+   set and the former resource limit is returned.
+
+   Raises :exc:`ProcessLookupError` when *pid* can't be found and
+   :exc:`PermissionError` when the user doesn't have ``CAP_SYS_RESOURCE`` for
+   the process.
+
+   Availability: Linux (glibc 2.13+)
+
+   .. versionadded:: 3.4
+
+
 These symbols define resources whose consumption can be controlled using the
 :func:`setrlimit` and :func:`getrlimit` functions described below. The values of
 these symbols are exactly the constants used by C programs.