WARNING 206: MISSING FUNCTION PROTOTYPE
ANSWER
The called function is unknown because no prototype declaration exists. Calls to unknown functions risk that the number of parameters may not correspond to the actual requirements. If this is the case, the function is called incorrectly.
The compiler has no way to check for missing or excessive parameters and their types. Include prototypes of the functions used in your program. Prototypes must be specified before the functions are actually called. The definition of a function automatically produces a prototype.
Error C267: 'function': requires ANSI-style prototype
What does this message mean?
ANSWER
This error message indicates that the function you are defining was prototyped with an empty parameter list but the definition includes parameters. Your function prototypes must match your function definitions. Find the prototype and either remove it or update it so that its arguments match that of the definition and everything will work OK.