| name | full path name of file to be created |
| dlen | length of data record in bytes |
| mlen | if ISVARLEN then max record length else ignored |
| key | primary index description, see isam indexes |
| mode | see open modes |
integer file identifier, starting at zero, or a negative value on failure, in which case the error code will be found in iserrno.
if successful, isbuild will return an isam file descriptor open in the specified mode and ready for use.
refer to Variable Length Records for more details regarding ISVARLEN.