R-value

R-value or rvalue may refer to:

• In computer science, a value considered independently of its storage location
• In computer science, a data value of a variable stored at some location in memory
• R-value (insulation) in building engineering, the efficiency of insulation of a house
• R-value (soils) in geotechnical engineering, the stability of soils and aggregates for pavement construction
• R-factor (crystallography), a measure of the agreement between the crystallographic model and the diffraction data
• In statistics, the Pearson product-moment correlation coefficient, or simply correlation coefficient
• In ophthalmic optics, the distance between the segment optical center and the segment top
• In solid mechanics, the Lankford coefficient

Programming

C++0x Move Semantics

rvalues denote temporary objects which are destroyed at the next semicolon (to be more precise: at the end of the full-expression that lexically contains the rvalue)

//examble:
class Object {};

Object a;
Object b;
Object c;

c = a + b;

in above sample "a" and "b" are stored automatically in invisible object called "rvalue". below we try to show it:

Object a;
Object b;
Object c;
{ //start brace
    Object rvalue = a.operator+( b );
    c = rvalue;
} //end brace removes rvalue

See also

• R rating (disambiguation)
• L-value (disambiguation)