Temporary object
A temporary object is an unnamed object created for an intermediate expression or initialization whose lifetime is limited by language rules.
100 C++ Mistakes and How to Avoid Them
A temporary object is an unnamed object created for an intermediate expression or value and typically given a limited lifetime.
- How it is used
- Uses temporary objects to identify avoidable construction and destruction costs in class operations and arithmetic expressions.
- How deep it goes
- Explains intermediate results, constructor and destructor costs, and operator remedies, but does not develop detailed lifetime rules.
- Examples
- Demonstrates Complex assignment, chained addition, operator+=, and incremental accumulation.
- What you can do after
- Diagnose unnecessary temporaries and reduce them by returning references and applying compound assignment where appropriate.
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Modern C, Third Edition
A temporary object is an unnamed C object created for an intermediate expression or initialization and given automatic temporary lifetime.
- How it is used
- Uses unnamed intermediate objects to explain automatic storage and compile-time type checking.
- How deep it goes
- Explains implicit creation and optimization, but stops short of a complete lifetime model for every temporary-expression context.
- Examples
- Demonstrates a returned struct accessed through mem().ory[0] and a compound literal used for macro argument checking.
- What you can do after
- Evaluate C expressions that create unnamed objects and recognize compound-literal techniques for assignment-compatibility checks.
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Related concepts
- copy assignment operatorused by · A copy assignment operator is a C++ special member function that copies state from one object into an already existing object of a compatible type.
- return value optimizationaddressed by · Return value optimization is a compiler optimization that constructs a function's returned object directly in the destination storage, eliminating unnecessary temporary objects and copy operations.
- incrementused by · Incrementing is the operation of increasing a numeric value by one.
- read-only objectkind of · A read-only object is an object that a program is not permitted to modify through its applicable access or type qualification.
- throw by valueused by · Throw by value is the C++ exception-handling technique of throwing an exception object as a value rather than as a pointer or reference.
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