error: expected ')' before '*' token

This kind of error is reported by compiler when it tries to parse sybols it does understand, because they were not reported to it - proper my_type_def.h header file is missing.

my_error_t my_function(my_type_t *my_pointer)
{
   ...
}

Here, because #include my_header.h (where my_type_t is defined) is missing, compiler is telling us this message.

Solution :
include proper headers!