Name mangling, also known as name decoration, is a technique used by compilers to encode additional information about the scope, type, linkage, or other identifying information of an identifier (function names, variable names, etc.) within its name. The primary purpose of name mangling is to support function overloading, which allows multiple functions with the same name but different parameter lists to coexist in a single program.
In C++, the compiler generates a mangled name for each function and variable based on their scopes and types. The mangled name is usually formed by concatenating the original name, parameter types, and other information, often using a prefix or suffix.
For example, suppose you have the following function:
int add(int a, int b)
{
return a + b;
}
The compiler might generate a mangled name such as _Z3addii, which encodes the function name add and its two int parameters.
The exact rules for name mangling are implementation and platform dependent. Different compilers may mangle names differently, which can lead to incompatibilities when attempting to link together object files or libraries compiled with different compilers.
Some tools, such as c++filt (included in GCC and Clang), can be used to demangle a mangled name back to the original identifier, which can be useful when debugging or working with symbol tables.
$ echo "_Z3addii" | c++filt
add(int, int)
In general, it is not necessary for you to understand the details of name mangling when writing code in C++, as the compiler handles it automatically. However, it can affect program behavior in some cases, such as when using external libraries or linking object files from different compilers.