1 Version 4.0 -- 5/1/89 DBIORDESC (UNIX only)
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NAME: DBIORDESC (UNIX only)
FUNCTION:
Provide program access to the UNIX file descriptor used by a
DBPROCESS to read data coming from SQL Server.
SYNTAX:
int DBIORDESC(dbproc)
DBPROCESS *dbproc;
COMMENTS:
DBIORDESC (UNIX only)Version 4.0 -- 5/1/89 2
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o This routine provides a way for an application to respond
effectively to multiple input streams. Depending on the nature
of your application, the time between a request for information
from SQL Server (usually made via a call to dbsqlsend()) and
SQL Server's response (read by calling dbsqlok(), dbresults(),
or dbnextrow()) may be significant. You may use this time to
service other parts of your application. The DBIORDESC() rou-
tine provides a way to obtain the I/O descriptor which a DBPRO-
CESS uses to read the data stream from SQL Server. This infor-
mation may then be used with various operating system facili-
ties (such as the UNIX select() call) to allow the application
to respond effectively to multiple input streams.
o The file descriptor returned by this routine may only be used
with operating system facilities that do not read data from the
incoming data stream. If data is read from this stream by any
means other than through a DB-Library routine, communications
3 Version 4.0 -- 5/1/89 DBIORDESC (UNIX only)
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between the front-end and SQL Server will become hopelessly
scrambled.
o An application can use the DB-Library DBRBUF() routine, in
addition to the UNIX select() function, to help determine
whether any more data from SQL Server is available for reading.
o A companion routine, DBIOWDESC(), provides access to the file
descriptor used to write data to SQL Server.
o For an example that illustrates the use of DBIORDESC() with
dbsqlsend() and dbsqlok(), see the DB-Library Reference Supple-
ment.
PARAMETERS:
dbproc - A pointer to the DBPROCESS structure that provides the
connection for a particular front-end/SQL Server process. It
contains all the information that DB-Library uses to manage
communications and data between the front end and SQL Server.
DBIORDESC (UNIX only)Version 4.0 -- 5/1/89 4
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RETURNS:
An integer file descriptor used by the specified DBPROCESS to
read data coming from SQL Server.
SEE ALSO:
dbcmd, DBIOWDESC, dbnextrow, DBRBUF, dbresults, dbsqlok,
dbsqlsend