Question

gcc 4.7.2
c89

Hello,

I am using the Apache Portable Runtime and looking at their typedef’s

typedef short apr_int16_t
typedef int apr_int16_t
typedef size_t apr_size_t /* This is basically the same, so what's the point */

etc.

1. So what is the point of all this?
2. When should you decided to use C’s built-in standard data types or typedef’s data types?

I just gave a example using the APR. However, I am also speaking generally as well. There is also the stdint.h header file that typedef’s data types.

Many thanks for any suggestions,

Answer 1

Great question.

1. So what is the point of all this?

   It’s meant to be for abstraction, but like anything else, it is sometimes misused/overused.
   Sometimes it’s necessary for backwards compatibility (e.g. typedef VOID void in Windows), sometimes it’s necessary for proper abstraction (e.g. typedef unsigned int size_t), and sometimes it’s completely pointless logically, but makes typing easier (e.g. typedef char const *LPCSTR in Windows).

2. When should you decided to use C’s built-in standard data types or typedef’s data types?

   If it makes something easier, or if it implements a proper abstraction barrier, use it.
   What exactly that means is something you’ll just have to learn over time.
   But don’t use it “just for kicks”!