Name decoration
|
|
In computer programming, name decoration provides a way of encoding additional information about the name of a function, structure, class or another datatype in order to pass more semantic information from the compilers to linkers.
Any object code produced by compilers is usually linked with other pieces of object code (produced by the same or another compiler) by a type of program called a linker. The linker needs a great deal of information on each program entity. For example, to correctly link a function it needs its name, the number of arguments, their type, and so on. To convey such information, a programmer may decorate the name is with additional control characters. For example, a C function called "MatrixMult" becomes:
MatrixMult@8
to indicate that the function arguments need 8 bytes of storage on the stack and -- assuming a fixed argument size of (say) 4 bytes (32 bits) -- that this function has 2 arguments. Other common name decoration actions may involve adding prefixes, usually with an abundance of underlines (like __func__), or some standard capitalization.
Many programming languages like C, Fortran and Pascal define standards for name decoration. Following such standards, object code produced by a compiler can get linked to object code produced by another compiler.
The C++ language does not define a standard decoration scheme, so each compiler uses its own. Combined with the fact that C++ decoration can become fairly complex (storing information about classes, default arguments, variable ownership, operator overloading, etc), this means that object code produced by different compilers is not usually linkable.
Some coders use a less forgiving (and more honest) term for this technique: name mangling.
External links
- Citations from CiteSeer (http://citeseer.ist.psu.edu/cis?q=Name+and+decoration)