Adding a section explaining how to fake variadic functions
diff --git a/README.md b/README.md
index 2526170..5a03a19 100644
--- a/README.md
+++ b/README.md
@@ -329,6 +329,23 @@
macro. When the last custom fake is reached the fake will keep calling the last custom
fake in the sequence. This macro works much like the SET_RETURN_SEQ macro.
+## Variadic Functions
+
+You can fake variadic functions using the macros <tt>FAKE_VALUE_FUNC_VARARG</tt>
+and <tt>FAKE_VOID_FUNC_VARARG</tt>. For instance:
+
+ FAKE_VALUE_FUNC_VARARG(int, fprintf, FILE *, const char*, ...);
+
+In order to access the variadic parameters from a custom fake function, declare a
+<tt>va_list</tt> parameter. For instance, a custom fake for <tt>fprintf()</tt>
+could call the real <tt>fprintf()</tt> like this:
+
+ int fprintf_custom(FILE *stream, const char *format, va_list ap) {
+ if (fprintf0_fake.return_val < 0) // should we fail?
+ return fprintf0_fake.return_val;
+ return vfprintf(stream, format, ap);
+ }
+
## How do I fake a function that returns a value by reference?
The basic mechanism that FFF provides you in this case is the custom_fake field described in the *Custom Return Value Delegate* example above.
