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C Naming Conventions

Geoffrey Hunter Author


This page explains my preferred naming convention style for C code.


All local variables (variables within a function) begin with a lower-case letter and use camel-case, including function pointers. Only the first letter in an acronym is capitalised, e.g.

void MyFunction() {
uint8_t activeGpsAnt;

All file-level and global variable use the same syntax except with an underscore in front of them.

uint8_t _activeGpsAnt;

void MyFunction() {
// code here...


Functions start with the file/module name, an underscore, and then a description. All functions use camel-case and begin with a capital letter. For example, a function in a file called Gps.c would look like...

void Gps_GetLocation();


Typedefs aways end in _t. The helps the reader instantly distinguish a data type from anything else, and also serves to distinguish user defined data types (e.g. uint8_t, myType_t) from system data types (e.g. char, double, int).


When it comes to capitalisation rules, acronyms are treated if they were a standard word, and only the first letter of the acronym is capitalised. For example, if you had a GPS variable, it would be named:

bool gpsEnabled = true;

Similarly, for functions: