diff options
Diffstat (limited to 'cpp/demo/Ice/nrvo/NrvoI.cpp')
| -rw-r--r-- | cpp/demo/Ice/nrvo/NrvoI.cpp | 32 |
1 files changed, 26 insertions, 6 deletions
diff --git a/cpp/demo/Ice/nrvo/NrvoI.cpp b/cpp/demo/Ice/nrvo/NrvoI.cpp index dea09e60bed..656a3e400f2 100644 --- a/cpp/demo/Ice/nrvo/NrvoI.cpp +++ b/cpp/demo/Ice/nrvo/NrvoI.cpp @@ -8,24 +8,34 @@ // ********************************************************************** #include <Ice/Ice.h> -#include <iostream> #include <NrvoI.h> using namespace std; NrvoI::NrvoI() : - _stringSeq(Demo::StringSeqSize, "hello") + _stringSeq(10, "hello") { } +// +// NRVO (Named Return Value Optimization): +// the return value is a stack-allocated variable, +// and there is only a single return path. +// Demo::StringSeq NrvoI::op1(const Ice::Current&) { cout << "running op1" << endl; - MyStringSeq seq = MyStringSeq(Demo::StringSeqSize, "hello"); + // + // Not "return MyStringSeq(10, "hello")", since this lacks a name. + // + MyStringSeq seq = MyStringSeq(10, "hello"); return seq; } +// +// No optimization: the return value is a data member. +// Demo::StringSeq NrvoI::op2(const Ice::Current&) { @@ -33,20 +43,30 @@ NrvoI::op2(const Ice::Current&) return _stringSeq; } + +// +// Operation with multiple return paths. +// Demo::StringSeq NrvoI::op3(int size, const Ice::Current&) { cout << "running op3" << endl; - MyStringSeq seq; if(size < 10) { + // + // RVO (Return Value Optimization): return value + // is constructed in place. + // return MyStringSeq(size, "hello"); } - seq = MyStringSeq(10, "hello"); + + // + // No optimization: NRVO requires a single return path. + // + MyStringSeq seq = MyStringSeq(10, "hello"); return seq; } - void NrvoI::shutdown(const Ice::Current& c) { |