Author: Armin Rigo <[email protected]>
Branch: extradoc
Changeset: r783:097e4f70c803
Date: 2016-08-31 19:18 +0200
http://bitbucket.org/pypy/pypy.org/changeset/097e4f70c803/
Log: Copy some documentation about ``-X track-resources`` here as well
diff --git a/compat.html b/compat.html
--- a/compat.html
+++ b/compat.html
@@ -116,6 +116,16 @@
<div class="syntax python"><pre><span></span><span class="n">f</span> <span
class="o">=</span> <span class="nb">open</span><span class="p">(</span><span
class="s2">"filename"</span><span class="p">,</span> <span
class="s2">"w"</span><span class="p">)</span><br/><span
class="n">f</span><span class="o">.</span><span class="n">write</span><span
class="p">(</span><span class="s2">"stuff"</span><span
class="p">)</span><br/><span class="n">f</span><span class="o">.</span><span
class="n">close</span><span class="p">()</span><br/></pre></div>
<p>or using the <tt class="docutils literal">with</tt> keyword</p>
<div class="syntax python"><pre><span></span><span class="k">with</span> <span
class="nb">open</span><span class="p">(</span><span
class="s2">"filename"</span><span class="p">,</span> <span
class="s2">"w"</span><span class="p">)</span> <span
class="k">as</span> <span class="n">f</span><span class="p">:</span><br/>
<span class="n">f</span><span class="o">.</span><span
class="n">write</span><span class="p">(</span><span
class="s2">"stuff"</span><span class="p">)</span><br/></pre></div>
+<p>The same problem–not closing your files–can also show up if your
+program opens a large number of files without closing them explicitly.
+In that case, you can easily hit the system limit on the number of file
+descriptors that are allowed to be opened at the same time.</p>
+<p>Since release 5.4, PyPy can be run with the command-line option <tt
class="docutils literal"><span class="pre">-X</span>
+<span class="pre">track-resources</span></tt> (as in, <tt class="docutils
literal">pypy <span class="pre">-X</span> <span
class="pre">track-resources</span> myprogram.py</tt>).
+This produces a ResourceWarning when the GC closes a non-closed file or
+socket. The traceback for the place where the file or socket was
+allocated is given as well, which aids finding places where <tt
class="docutils literal">close()</tt>
+is missing.</p>
<p>Similarly, remember that you must <tt class="docutils literal">close()</tt>
a non-exhausted
generator in order to have its pending <tt class="docutils
literal">finally</tt> or <tt class="docutils literal">with</tt>
clauses executed immediately:</p>
diff --git a/source/compat.txt b/source/compat.txt
--- a/source/compat.txt
+++ b/source/compat.txt
@@ -86,6 +86,18 @@
with open("filename", "w") as f:
f.write("stuff")
+The same problem---not closing your files---can also show up if your
+program opens a large number of files without closing them explicitly.
+In that case, you can easily hit the system limit on the number of file
+descriptors that are allowed to be opened at the same time.
+
+Since release 5.4, PyPy can be run with the command-line option ``-X
+track-resources`` (as in, ``pypy -X track-resources myprogram.py``).
+This produces a ResourceWarning when the GC closes a non-closed file or
+socket. The traceback for the place where the file or socket was
+allocated is given as well, which aids finding places where ``close()``
+is missing.
+
Similarly, remember that you must ``close()`` a non-exhausted
generator in order to have its pending ``finally`` or ``with``
clauses executed immediately:
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