When a problem occurs in any HTK tool, either an error or warning message is printed. The format of these messages is as follows
HTool: WARNING [-nnnn]
Function: Brief explanation
HTool: ERROR [+nnnn]
Function: Brief explanation
The message consists of four parts. On the first line is the tool name and the error number . On the second line is the function in which the problem occurred and a brief textual explanation. When an error occurs the message is printed to standard error and the program terminates immediately but for warnings the message is sent to standard output and execution continues. The reason for sending warnings to standard output is so that they are synchronised with any trace output.
Error numbers in HTK are allocated on a module by module and tool by tool basis in blocks of 100 as shown by the table shown overleaf. Within each block of 100 numbers the first 20 (0 - 19) and the final 10 (90-99) are reserved for standard types of error which are common to all tools and library modules.
All other codes are module or tool specific.