fixup: add 34.9.10.1

Author: jensmaurer

source/exec.tex

@@ -2567,7 +2567,47 @@
 
 \rSec3[exec.adapt.general]{General}
 
+\pnum
+Subclause \ref{exec.adapt} specifies a set of sender adaptors.
+
+\pnum
+The bitwise inclusive \logop{or} operator is overloaded
+for the purpose of creating sender chains.
+The adaptors also support function call syntax with equivalent semantics.
 
+\pnum
+Unless otherwise specified:
+\begin{itemize}
+\item
+A sender adaptor is prohibited from causing observable effects,
+apart from moving and copying its arguments,
+before the returned sender is connected with a receiver using \tcode{connect},
+and \tcode{start} is called on the resulting operation state.
+\item
+A parent sender\iref{exec.async.ops} with a single child sender \tcode{sndr} has
+an associated attribute object equal to
+\tcode{\exposid{FWD-ENV}(get_env(sndr))}\iref{exec.fwd.env}.
+\item
+A parent sender with more than one child sender has
+an associated attributes object equal to \tcode{empty_env\{\}}.
+\item
+When a parent sender is connected to a receiver \tcode{rcvr},
+any receiver used to connect a child sender has
+an associated environment equal to \tcode{\exposid{FWD-ENV}(get_env(rcvr))}.
+\item
+These requirements apply to any function
+that is selected by the implementation of the sender adaptor.
+\end{itemize}
+
+\pnum
+If a sender returned from a sender adaptor specified in \ref{exec.adapt}
+is specified to include \tcode{set_error_t(Err)}
+among its set of completion signatures
+where \tcode{decay_t<Err>} denotes the type \tcode{exception_ptr},
+but the implementation does not potentially evaluate
+an error completion operation with an \tcode{exception_ptr} argument,
+the implementation is allowed to omit
+the \tcode{exception_ptr} error completion signature from the set.
 
 \rSec1[exec.util]{Sender/receiver utilities}