What are the most common naming conventions in C?

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, butshouldn't be called directly, or haveobscure uses, or whatever: one or moreunderscores at the beginning:_refrobnicate_data_tables(), _destroy_cache().

"Struct pointers" aren't entities that need a naming convention clause to cover them. They're just struct WhatEver *. DON'T hide the fact that there is a pointer involved with a clever and "obvious" typedef. It serves no purpose, is longer to type, and destroys the balance between declaration and access.

You know, I like to keep it simple, but clear... So here's what I use, in C:

• Trivial Variables: i,n,c,etc... (Only one letter. If one letter isn'tclear, then make it a Local Variable)
• Local Variables: camelCase
• Global Variables: g_camelCase
• Const Variables: ALL_CAPS
• Pointer Variables: add a p_ to the prefix. For global variables it would be gp_var, for local variables p_var, for const variables p_VAR. If far pointers are used then use an fp_ instead of p_.
• Structs: ModulePascalCase (Module = full module name, or a 2-3 letter abbreviation, but still in PascalCase.)
• Struct Member Variables: camelCase
• Enums: ModulePascalCase
• Enum Values: ALL_CAPS
• Public Functions: ModulePascalCase
• Private Functions: PascalCase
• Macros: PascalCase

I typedef my structs, but use the same name forboth the tag and the typedef. The tag is not meant to be commonly used.Instead it's preferrable to use the typedef. I also forward declare the typedef in the public module header for encapsulation and so that I can use the typedef'd name in the definition.

Full struct Example:

typdef struct UtilsExampleStruct UtilsExampleStruct;struct UtilsExampleStruct{    int var;    UtilsExampleStruct *p_link;};