typedef在内部如何工作？

Question

As the question goes how does typedef work internally?

PS : I did search in various websites including Wikipedia and various. But none of them answer this. Hence the question.

To clarify further : I did get to what it does but how it does is the question.

Answer 1

typedef is the keyword in C , which provides the programmer a tool to make an alias of own

data type from the other types or existing built-in types.

This is how the language is and this is how it's implemented.

typedef <given_type> <new_type>

FYI : if you do

int a it parsed by compiler and then it came to know that a is a variable of type int . And accordingly memory is assigned and all.

Similarly whenever typedef keyword found then it assumes that the type just following it is the old_type and other new identifier is new_type .

EDIT :

ISO c99 : Storage-class specifiers

The typedef specifier is called a ''storage-class specifier'' for syntactic convenience only.If, in a parameter declaration, an identifier can be treated either as a typedef name or as a parameter name, it shall be taken as a typedef name.A typedef declaration does not introduce a new type, only a synonym for the type so specified

Answer 2

How any compiler handles a typedef isn't specified; most likely the type information is saved as part of the symbol table entry for that name, and everywhere the type name is encountered in the source code, the equivalent type information is substituted during translation.