The document provides coding style guidelines for functions including: ensuring functions with multiple return statements properly use a flag variable; refactoring local variable names to include the function name to avoid conflicts; creating a return variable; avoiding register variables; and not using ++ and -- operators in statements.

1. 1) !!! You must make sure function have right "return" when it have more than
one "return". !!! (eg. jpeg>>pgetc())
how-to: make a flag to remember
2) Refacte all the virables names "var" to "FUNCTION_NAME_var" in the function
to make sure it's global safety.
3) Create new "function_name_return" varable .
4) Cancel register variables.
5) "++" "--" can't be used in statement.