ERROR - how BSORT handles errors.

BSORT extracts all the key information from each record as it is read in. This information is added to the end of the record immediately, to make it easy to detect the keys when passing through the records.

In the course of extracting key information, several errors may occur; for example

a key is found with a length less than or equal to zero bits;
a key may be found with an incorrect format -- for example, the key-field may specify +Numeric but the record contains non-numeric data;
the key may be too short -- for example, "Length=9bytes" may be specified for the key but the end of the record comes after only two bytes;
the key may be missing -- for example, "Field=10,skip=':'" may be specified but there are only three colons in the record, or "After=30c" may be specified but the record is only 10 characters long.

If any of these situations occur, the key is in error. This would normally imply that the entire record is erroneous; however, if "-Error" was specified in the key-string for the erroneous key, the error is disregarded and the record is NOT marked as erroneous.

If the record is marked as erroneous, the "Error=" disposition is checked. If "Error=Stop" was specified on the command line, BSORT terminates.

If the "Error=" disposition is not "Stop", BSORT makes some attempt to include the record in the sorting process. Thus BSORT tries to correct the erroneous key. If the key is merely shorter than expected, it is padded to the correct length by adding zero bits on the right. With character data, this means appending ASCII nulls (octal 000); with numeric data, this essentially means adding "0" characters. The expanded key is added to the key information on the end of the record so that it can participate in the sorting process. Any erroneous EIS data field will be set to negative infinity (so that it will sort first if +AScending is specified).

If the key is missing or invalid for some reason, a key consisting of zero bits is supplied. With character data, this means a string of ASCII nulls; with numeric data, this means the number zero. The supplied key is added to the key information on the end of the record.

If the "Error=" code is "Report" or "Ignore", erroneous records will be written to the RejectFile (if one exists) after all the records have been sorted. Thus the RejectFile will always be sorted, making it easier to merge erroneous records with the correct ones, if desired. If the "Error=" code is "First" or "Last", erroneous records will appear in the appropriate location within the sorted output and will NOT be written to the RejectFile.

If "-Error" is specified in the key-string, the erroneous key is padded or supplied with zero bits without marking the entire record as erroneous. The sort takes place using this zero value. Since the record is not regarded as erroneous, it is not written to the RejectFile.

ERROR - how BSORT handles errors.

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