add a member of enum - a symbolic constant
enum_id - id of enum
name - name of symbolic constant. Must be unique
in the program.
value - value of symbolic constant.
bmask - bitmask of the constant
ordinary enums accept only -1 as a bitmask
all bits set in value should be set in bmask too
returns: 0-ok, otherwise error code CONST_ERROR_...
long add_enum_member(long enum_id, string name, long value, long bmask);
#define CONST_ERROR_NAME 1 // already have member with this name (bad name)
#define CONST_ERROR_VALUE 2 // already have member with this value
#define CONST_ERROR_ENUM 3 // bad enum id
#define CONST_ERROR_MASK 4 // bad bmask
#define CONST_ERROR_ILLV 5 // bad bmask and value combination (~bmask & value != 0)