MuPDF Coding Style


Functions should be named according to one of the following schemes:

Prefixes are mandatory for exported functions, macros, enums, globals and types.

Prefixes are optional (but encouraged) for private functions and types.

Avoid using 'get' as this is a meaningless and redundant filler word.

These words are reserved for reference counting schemes:

When searching for an object or value, the name used depends on whether returning the value is passing ownership:


Various different integer types are used throughout MuPDF.

In general:

In addition, we use floats (and avoid doubles when possible), assumed to be IEEE compliant.

Reference counting

Reference counting uses special words in functions to make it easy to remember and follow the rules.

Words that take ownership: new, find, load, open, keep.

Words that release ownership: drop.

If an object is returned by a function with one of the special words that take ownership, you are responsible for freeing it by calling "drop" or "free", or "close" before you return. You may pass ownership of an owned object by return it only if you name the function using one of the special words.

Any objects returned by functions that do not have any of these special words, are borrowed and have a limited life time. Do not hold on to them past the duration of the current function, or stow them away inside structs. If you need to keep the object for longer than that, you have to either "keep" it or make your own copy.