Can we place "typedef" specifier anywhere in the declaration? [duplicate]

Question

The syntax of typedef specifier :

typedef <existing_name> <alias_name>

for example:

typedef long unsigned int Int;

It's working fine.

But, If I place typedef anywhere in the declaration, Like this:

long unsigned typedef int Int;

Then, It's also working fine.

Why? Can we place typedef anywhere in the declaration?

Shing

why not? int short static someVar; is also valid, right? – Assuan

Because the C standard specifies that. Read n1570 – Narcoma

Good but no good, you could have googled something like "typedef declaration ordering". -Edit NVM you need to know typedef is a "storage-class" to find the dupe effectively. – Conklin

C standard says that on a syntactic point of view typedef is just a storage class specifier like extern or static, so it can be intermixed with the type declarator. – Gauze

@rsp Please do not put language tags on question title, there are tags fields dedicated for that purpose. – Assuan

Similar to this question – Mathilda

Answer 1

First of all, quoting from §6.11.5, "Future language directions"

1 The placement of a storage-class specifier other than at the beginning of the declaration specifiers in a declaration is an obsolescent feature.

So, do not rely on this, as it may be removed in the future.

---

That said, to understand why this works, check the C11 standard, chapter §6.7.2:

[...] the type specifiers may occur in any order, possibly intermixed with the other declaration specifiers.

From §6.7.1, we know typedef is a storage-class specifier (one particular sort of a declaration specifier), so it can be placed after (or before) the type specifier (i.e., can be intermixed). It does not change anything.

Assuan

Answer 2

This is indeed allowed by the C standard. typedef is a storage class specifier and if you look at the grammar given in the C standard (N1570, latest draft for C11, §6.7 p1):

Syntax
declaration:
. declaration-specifiers init-declarator-list(opt) ;
. static_assert-declaration
declaration-specifiers:
. storage-class-specifier declaration-specifiers(opt)
. type-specifier declaration-specifiers(opt)
. type-qualifier declaration-specifiers(opt)
. function-specifier declaration-specifiers(opt)
. alignment-specifier declaration-specifiers(opt)
init-declarator-list:
. init-declarator
. init-declarator-list , init-declarator
init-declarator:
. declarator
. declarator = initializer

the storage class specifier can appear after other declaration specifiers like the type specifier.

But you shouldn't use it, it's obsolescent, see §6.11.5:

The placement of a storage-class specifier other than at the beginning of the declaration specifiers in a declaration is an obsolescent feature.

Lakendra