NaCl docs: mention static libraries for SJLJ

native_client_sdk/src/doc/reference/pnacl-c-cpp-language-support.rst

 ============================
 PNaCl C/C++ Language Support
 ============================
 
 .. contents::
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 Source language support
@@ skipping 165 matching lines @@
 ======================
 
 PNaCl currently supports C++ exception handling through ``setjmp()`` and
 ``longjmp()``, which can be enabled with the ``--pnacl-exceptions=sjlj``
 linker flag. Exceptions are disabled by default so that faster and
 smaller code is generated, and ``throw`` statements are replaced with
 calls to ``abort()``. The usual ``-fno-exceptions`` flag is also
 supported. PNaCl will support full zero-cost exception handling in the
 future.
 
+.. note:: When using naclports_ or other prebuilt static libraries, you'll want
+          to make sure you rebuild these libraries with exception handling

[Mark Seaborn, 2015/02/18 18:00:08]

How does a developer do that?

Isn't -fexceptions the default when compiling C++?

[JF, 2015/02/18 18:19:14]

What do you mean? There are instructions on this above, how would you suggest
improving them?
Yes, it's implied above when -fno-exceptions is mentioned. Do you suggest saying
-fexceptions is the default?

[Mark Seaborn, 2015/02/18 18:36:03]

Sorry, I didn't look at all of the context.

Saying "rebuild" here suggests that nacl-ports uses -fno-exceptions by default. 
Is that the case?

If not, maybe say "...make sure these libraries are not being built with
-fno-exceptions"?

[JF, 2015/02/18 18:43:28]

I clarified a few things, PTAL.

+          enabled. For naclports, you'll want to modify the port's ``build.sh``.
+
+.. _naclports: https://code.google.com/p/naclports
+
 NaCl supports full zero-cost C++ exception handling.
 
 Inline Assembly
 ===============
 
 Inline assembly isn't supported by PNaCl because it isn't portable. The
 one current exception is the common compiler barrier idiom
 ``asm("":::"memory")``, which gets transformed to a sequentially
 consistent memory barrier (equivalent to ``__sync_synchronize()``). In
 PNaCl this barrier is only guaranteed to order ``volatile`` and atomic
@@ skipping 273 matching lines @@
   A similar feature is **thread suspension**: The ability to
   asynchronously suspend and resume a thread and inspect or modify its
   execution state (such as register state).
 
   Neither PNaCl nor NaCl currently support asynchronous interruption
   or suspension of threads.
 
 If PNaCl were to support either of these, the interaction of
 ``volatile`` and atomics with same-thread signal handling would need
 to be carefully detailed.