What are the most common naming conventions in C?

Question

What are the naming conventions commonly use in C? I know there are at least two:

1. GNU / linux / K&R with lower_case_functions
2. ? name ? with UpperCaseFoo functions

I am talking about C only here. Most of our projects are small embedded systems in which we use C.

Here is the one I am planning on using for my next project:

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C Naming Convention

Struct              TitleCase
Struct Members      lower_case or lowerCase

Enum                ETitleCase
Enum Members        ALL_CAPS or lowerCase

Public functions    pfx_TitleCase (pfx = two or three letter module prefix)
Private functions   TitleCase
Trivial variables   i,x,n,f etc...
Local variables     lower_case or lowerCase
Global variables    g_lowerCase or g_lower_case (searchable by g_ prefix)

Answer 1

The most important thing here is consistency. That said, I follow the GTK+ coding convention, which can be summarized as follows:

1. All macros and constants in caps: MAX_BUFFER_SIZE, TRACKING_ID_PREFIX.
2. Struct names and typedef's in camelcase: GtkWidget, TrackingOrder.
3. Functions that operate on structs: classic C style: gtk_widget_show(), tracking_order_process().
4. Pointers: nothing fancy here: GtkWidget *foo, TrackingOrder *bar.
5. Global variables: just don't use global variables. They are evil.
6. Functions that are there, but shouldn't be called directly, or have obscure uses, or whatever: one or more underscores at the beginning: _refrobnicate_data_tables(), _destroy_cache().