Fork channel

Create a new channel as a copy of main.

Rename channel

Rename main to:

Delete channel

Delete main? This cannot be undone.

cxx-reference.cpp
// Test this without pch.
// RUN: %clang_cc1 -x c++ -triple %itanium_abi_triple -std=c++11 -include %S/cxx-reference.h -fsyntax-only -emit-llvm -o - %s

// Test with pch.
// RUN: %clang_cc1 -x c++ -triple %itanium_abi_triple -std=c++11 -emit-pch -o %t %S/cxx-reference.h
// RUN: %clang_cc1 -x c++ -triple %itanium_abi_triple -std=c++11 -include-pch %t -fsyntax-only -emit-llvm -o - %s