C++
- Getting started with C++
- Awesome Book
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- Alignment
- Argument Dependent Name Lookup
- Arithmitic Metaprogramming
- Arrays
- Atomic Types
- Attributes
- auto
- Basic input/output in c++
- Basic Type Keywords
- Bit fields
- Bit Manipulation
- Bit Operators
- Build Systems
- C incompatibilities
- C++ Containers
- C++ Debugging and Debug-prevention Tools & Techniques
- C++ function "call by value" vs. "call by reference"
- C++ Streams
- C++11 Memory Model
- Callable Objects
- Classes/Structures
- Client server examples
- Common compile/linker errors (GCC)
- Compiling and Building
- Concurrency With OpenMP
- Const Correctness
- const keyword
- Constant class member functions
- constexpr
- Copy Elision
- Purpose of copy elision
- Copy initialization elision
- Guaranteed copy elision
- Named return value elision
- Parameter elision
- Return value elision
- Copying vs Assignment
- Curiously Recurring Template Pattern (CRTP)
- Data Structures in C++
-
Date and time using
header - decltype
- Design pattern implementation in C++
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- More undefined behaviors in C++
- Move Semantics
- mutable keyword
- Mutexes
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- One Definition Rule (ODR)
- Operator Overloading
- operator precedence
- Optimization
- Optimization in C++
- Overload resolution
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- Return Type Covariance
- Returning several values from a function
- RTTI: Run-Time Type Information
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- Side by Side Comparisons of classic C++ examples solved via C++ vs C++11 vs C++14 vs C++17
- Singleton Design Pattern
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- Standard Library Algorithms
- static_assert
- std::any
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- std::function: To wrap any element that is callable
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- std::string
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- The ISO C++ Standard
- The Rule of Three, Five, And Zero
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- Unnamed types
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- User-Defined Literals
- Using declaration
- Using std::unordered_map
- Value and Reference Semantics
- Value Categories
- Variable Declaration Keywords
- Virtual Member Functions
C++ Copy Elision Parameter elision
Example
When you pass an argument to a function, and the argument is a prvalue expression of the function's parameter type, and this type is not a reference, then the prvalue's construction can be elided.
void func(std::string str) { ... }
func(std::string("foo"));
This says to create a temporary string, then move it into the function parameter str. Copy elision permits this expression to directly create the object in str, rather than using a temporary+move.
This is a useful optimization for cases where a constructor is declared explicit. For example, we could have written the above as func("foo"), but only because string has an implicit constructor that converts from a const char* to a string. If that constructor was explicit, we would be forced to use a temporary to call the explicit constructor. Copy elision saves us from having to do a needless copy/move.
