| Discussion:
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The INQUIRE statement performs the same function as the
READ
statement, and is able to retrieve records that have been
extracted.
Notes:
- The INQUIRE statement is available in Comet 504 and
greater. Executing the INQUIRE statement under previous
versions of Comet generates an exception 91).
- On type N directories, Comet uses system-level record locking to synchronize
access to files. This includes EXTRACT. An INQUIRE statement cannot break into this record
lock to get the record. Record locking is a facility provided by Windows/DOS. Since this
feature is beyond Comet's control, performing an INQUIRE on an extracted record in a type
N directory will result a wait until the record becomes available.
The CometServe file system, on the other hand, has control of all activity on each file.
It is not subject to the same restrictions that record locking imposes. Thus, on type S
directories, the INQUIRE statement is able to retrieve records that have been extracted.
- The optional index parameter is used to access a particular
record in a keyed file. If an index is not specified, the file
is read in key-sequential order.
- When the index parameter is used, the index (key) can be any
valid string expression. If the key index is shorter than the
file key size, it is padded with trailing blanks prior to the
key search. If it is longer than the key size, excess trailing
characters are truncated prior to the key search. If the key
index is not found in the key list, the file pointer is
positioned at the next key and an exception 32 is encountered.
- The INQUIRE statement automatically advances the file pointer
to the next record in the file.
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