addseverity - introduce new severity classes
int addseverity(int severity, const char *s);
This function allows the introduction of new severity classes which can be addressed by the severity parameter of the fmtmsg(3) function. By default that latter function only knows how to print messages for severity 0-4 (with strings (none), HALT, ERROR, WARNING, INFO). This call attaches the given string s to the given value severity. If s is NULL, the severity class with the numeric value severity is removed. It is not possible to overwrite or remove one of the default severity classes. The severity value must be nonnegative.
Upon success, the value MM_OK is returned. Upon error, the return value is MM_NOTOK. Possible errors include: out of memory, attempt to remove a nonexistent or default severity class.
New severity classes can also be added by setting the environment variable SEV_LEVEL.
This function is not specified in the X/Open Portability Guide although the fmtsmg() function is. It is available on System V systems.