[res.on.exception.handling] Add front matter on exception propagation

Author: JohelEGP

source/lib-intro.tex

@@ -3208,6 +3208,23 @@
 for a non-virtual function
 by adding a non-throwing exception specification.
 
+\pnum
+Some functions defined in the \Cpp{} standard library
+are specified to propagate exceptions thrown by a described evaluation.
+Unless stated otherwise,
+exceptions thrown due to evaluating the subexpression
+that implements the described evaluation
+up to the complete evaluation of its enclosing full-expression
+are also propagated.
+\begin{note}
+This includes exceptions thrown as part of
+initializing parameters,
+evaluating default arguments, and
+destroying temporaries
+(including discarded-value expressions)
+\iref{expr.call}.
+\end{note}
+
 \rSec3[value.error.codes]{Value of error codes}
 
 \pnum