From 868ecad32ba7fb3eb763642e22ebb06938fdb359 Mon Sep 17 00:00:00 2001
From: Mike Pall <mike>
Date: Sun, 8 May 2011 22:34:40 +0200
Subject: FFI: Add ffi.errno().

---
 doc/ext_ffi_api.html | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

(limited to 'doc')

diff --git a/doc/ext_ffi_api.html b/doc/ext_ffi_api.html
index b1b42878..2d69cb49 100644
--- a/doc/ext_ffi_api.html
+++ b/doc/ext_ffi_api.html
@@ -336,6 +336,28 @@ objects.
 
 <h2 id="util">Utility Functions</h2>
 
+<h3 id="ffi_errno"><tt>err = ffi.errno()</tt></h3>
+<p>
+Returns the error number set by the last C&nbsp;function call which
+indicated an error condition.
+</p>
+<p>
+This function offers a portable and OS-independent way to get the error
+number. Note that only <em>some</em> C&nbsp;functions set the error
+number. And it's only significant if the function actually indicated an
+error condition (e.g. with a return value of <tt>-1</tt> or
+<tt>NULL</tt>). Otherwise, it may or may not contain any previously set
+value.
+</p>
+<p>
+You're advised to call this function only when needed and as close as
+possible after the return of the related C&nbsp;function. The
+<tt>errno</tt> value is preserved across hooks, memory allocations,
+invocations of the JIT compiler and other internal VM activity. The same
+applies to the value returned by <tt>GetLastError()</tt> on Windows, but
+you need to declare and call it yourself.
+</p>
+
 <h3 id="ffi_string"><tt>str = ffi.string(ptr [,len])</tt></h3>
 <p>
 Creates an interned Lua string from the data pointed to by
-- 
cgit v1.2.3-55-g6feb