Question

Both this style:

struct _something
{
   ...
};
typedef struct _something someting;

and that style:

typedef struct _something
{
  ...
} something;

are correct typedef declarations in C.
Note that the presence of the structure declaration in the header file is made on purpose: I need to have access to the inner components of the structure somewhere else.

One drawback of the first declaration is that when you use any IDE, the automatic “jump to declaration” often directs you to the typedef struct _something someting; instead of giving you directly the real structure definition.

In the second method, you get directly to the structure definition.

Is there a reason why one would use the first method?
The code I’m working on is full with these…
Is it simply a bad/good habit from the maintainers?

Answer 1

This discussion thread gives a good overview of the topic, and highlights an important reason to use the first style:

This style separates type definition (which is not what typedef does)
from typename synonym creation (which is what typedef does), and retains
a strong correspondence between type name and type synonym without the
disadvantage of using the same name for both (which can confuse some
debuggers, and in any case is a pain for grep).