Internals
[The db-lib API]

Functions called within db-lib for self-help. More...

Classes
struct	_dblib_error_message
Defines
#define	DBSETLLABELED(x, y)   dbsetlbool((x), (y), DBSETLABELED)
	Alternative way to set login packet fields.
#define	DBSETLVERSION(login, version)   dbsetlversion((login), (version))
	maps to the Microsoft (lower-case) function.
Typedefs
typedef _dblib_error_message	DBLIB_ERROR_MESSAGE
Functions
int	_dblib_check_and_handle_interrupt (void *vdbproc)
	check interrupts for libtds.
RETCODE	dbcmdrow (DBPROCESS *dbproc)
	See if the current command can return rows.
DBINT	dbcount (DBPROCESS *dbproc)
	Get count of rows processed.
int	dbcurcmd (DBPROCESS *dbproc)
	Get number of the row just returned.
DBINT	dbcurrow (DBPROCESS *dbproc)
	Get number of the row currently being read.
DBBOOL	dbdead (DBPROCESS *dbproc)
	Check if dbproc is an ex-parrot.
DBINT	dbfirstrow (DBPROCESS *dbproc)
	Get number of the first row in the row buffer.
int	dbiordesc (DBPROCESS *dbproc)
	Get file descriptor of the socket used by a DBPROCESS to read data coming from the server. (!).
int	dbiowdesc (DBPROCESS *dbproc)
	Get file descriptor of the socket used by a DBPROCESS to write data coming to the server. (!).
DBINT	dblastrow (DBPROCESS *dbproc)
	Get number of the last row in the row buffer.
int	dbperror (DBPROCESS *dbproc, DBINT msgno, long errnum,...)
	Call client-installed error handler.
RETCODE	dbrows (DBPROCESS *dbproc)
	Indicate whether a query returned rows.
STATUS	dbrowtype (DBPROCESS *dbproc)
	Get returned row's type.
void	dbsetavail (DBPROCESS *dbproc)
	Mark a DBPROCESS as "available".
RETCODE	dbsetlbool (LOGINREC *login, int value, int which)
	Set a boolean value in a LOGINREC structure.
RETCODE	dbsetllong (LOGINREC *login, long value, int which)
	Set an integer value in a LOGINREC structure.
RETCODE	dbsetlname (LOGINREC *login, const char *value, int which)
	Set the value of a string in a LOGINREC structure.
RETCODE	dbsetlshort (LOGINREC *login, int value, int which)
	Set an integer value in a LOGINREC structure.
int	dbtds (DBPROCESS *dbproc)
	Get the TDS version in use for dbproc.
static int	default_err_handler (DBPROCESS *dbproc, int severity, int dberr, int oserr, char *dberrstr, char *oserrstr)
	default error handler for db-lib (handles library-generated errors)
DBPROCESS *	tdsdbopen (LOGINREC *login, const char *server, int msdblib)
	Form a connection with the server.

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Detailed Description

Functions called within db-lib for self-help.

These functions are of interest only to people hacking on the FreeTDS db-lib implementation.

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Define Documentation

DBSETLLABELED (  x, y   )     dbsetlbool((x), (y), DBSETLABELED)

Alternative way to set login packet fields. See also: dbsetllabeled()

DBSETLVERSION (  login, version   )     dbsetlversion((login), (version))

maps to the Microsoft (lower-case) function. See also: dbsetlversion()

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Typedef Documentation

typedef struct _dblib_error_message DBLIB_ERROR_MESSAGE

For internal use only. Remarks: member msgno Vendor-defined message number member severity Is passed to the error handler member msgtext Text of message

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Function Documentation

int _dblib_check_and_handle_interrupt (  void *  vdbproc  )

check interrupts for libtds. Parameters: vdbproc  a DBPROCESS pointer, contains all information needed by db-lib to manage communications with the server. See also: DBDEAD(), dbsetinterrupt().

RETCODE dbcmdrow (  DBPROCESS *  dbproc  )

See if the current command can return rows. For internal use only. Parameters: dbproc  contains all information needed by db-lib to manage communications with the server. Return values: SUCCEED  Yes, it can. FAIL  No, it can't. Remarks: Use DBCMDROW() macro instead. See also: DBCMDROW(), dbnextrow(), dbresults(), DBROWS(), DBROWTYPE().

DBINT dbcount (  DBPROCESS *  dbproc  )

Get count of rows processed. For internal use only. Parameters: dbproc  contains all information needed by db-lib to manage communications with the server. Returns: for insert/update/delete, count of rows affected. for select, count of rows returned, after all rows have been fetched. See also: DBCOUNT(), dbnextrow(), dbresults().

int dbcurcmd (  DBPROCESS *  dbproc  )

Get number of the row just returned. For internal use only. Parameters: dbproc  contains all information needed by db-lib to manage communications with the server. See also: DBCURROW(). Todo: Unimplemented.

DBINT dbcurrow (  DBPROCESS *  dbproc  )

Get number of the row currently being read. For internal use only. Parameters: dbproc  contains all information needed by db-lib to manage communications with the server. Returns: ostensibly the row number, or 0 if no rows have been read yet. Return values: 0  Always. See also: DBCURROW(), dbclrbuf(), DBFIRSTROW(), dbgetrow(), DBLASTROW(), dbnextrow(), dbsetopt(),. Todo: Unimplemented.

DBBOOL dbdead (  DBPROCESS *  dbproc  )

Check if dbproc is an ex-parrot. For internal use only. Parameters: dbproc  contains all information needed by db-lib to manage communications with the server. Return values: TRUE  process has been marked dead. FALSE  process is OK. Remarks: dbdead() does not communicate with the server. Unless a previously db-lib marked dbproc dead, dbdead() returns FALSE. See also: dberrhandle().

DBINT dbfirstrow (  DBPROCESS *  dbproc  )

Get number of the first row in the row buffer. For internal use only. Parameters: dbproc  contains all information needed by db-lib to manage communications with the server. See also: DBFIRSTROW(), dbclrbuf(), DBCURROW(), dbgetrow(), DBLASTROW(), dbnextrow(), dbsetopt().

int dbiordesc (  DBPROCESS *  dbproc  )

Get file descriptor of the socket used by a DBPROCESS to read data coming from the server. (!). For internal use only. Parameters: dbproc  contains all information needed by db-lib to manage communications with the server. See also: dbcmd(), DBIORDESC(), DBIOWDESC(), dbnextrow(), dbpoll(), DBRBUF(), dbresults(), dbsqlok(), dbsqlsend().

int dbiowdesc (  DBPROCESS *  dbproc  )

Get file descriptor of the socket used by a DBPROCESS to write data coming to the server. (!). For internal use only. Parameters: dbproc  contains all information needed by db-lib to manage communications with the server. See also: dbcmd(), DBIORDESC(), DBIOWDESC(), dbnextrow(), dbpoll(), DBRBUF(), dbresults(), dbsqlok(), dbsqlsend().

DBINT dblastrow (  DBPROCESS *  dbproc  )

Get number of the last row in the row buffer. For internal use only. Parameters: dbproc  contains all information needed by db-lib to manage communications with the server. See also: DBLASTROW(), dbclrbuf(), DBCURROW(), DBFIRSTROW(), dbgetrow(), dbnextrow(), dbsetopt().

int dbperror (  DBPROCESS *  dbproc, DBINT  msgno, long  errnum,   ... )

Call client-installed error handler. For internal use only. Parameters: dbproc  contains all information needed by db-lib to manage communications with the server. msgno  identifies the error message to be passed to the client's handler. errnum  identifies the OS error (errno), if any. Use 0 if not applicable. Returns: the handler's return code, subject to correction and adjustment for vendor style: INT_CANCEL The db-lib function that encountered the error will return FAIL. INT_TIMEOUT The db-lib function will cancel the operation and return FAIL. dbproc remains useable. INT_CONTINUE The db-lib function will retry the operation. Remarks: The client-installed handler may also return INT_EXIT. If Sybase semantics are used, this function notifies the user and calls exit(3). If Microsoft semantics are used, this function returns INT_CANCEL. If the client-installed handler returns something other than these four INT_* values, or returns timeout-related value for anything but SYBETIME, it's treated here as INT_EXIT (see above). Instead of sprinkling error text all over db-lib, we consolidate it here, where it can be translated (one day), and where it can be mapped to the TDS error number. The libraries don't use consistent error numbers or messages, so when libtds has to emit an error message, it can't include the text. It can pass its error number to a client-library function, which will interpret it, add the text, call the application's installed handler (if any) and return the handler's return code back to the caller. The call stack may look something like this: application db-lib function (encounters error) dbperror error handler (installed by application) The error handling in this case is unambiguous: the caller invokes this function, the client's handler returns its instruction, which the caller receives. Quite often the caller will get INT_CANCEL, in which case it should put its house in order and return FAIL. The call stack may otherwise look something like this: application db-lib function libtds function (encounters error) _dblib_handle_err_message dbperror error handler (installed by application) Because different client libraries specify their handler semantics differently, and because libtds doesn't know which client library is in charge of any given connection, it cannot interpret the raw return code from a db-lib error handler. For these reasons, libtds calls _dblib_handle_err_message, which translates between libtds and db-lib semantics. See also: dberrhandle(), _dblib_handle_err_message().

RETCODE dbrows (  DBPROCESS *  dbproc  )

Indicate whether a query returned rows. For internal use only. Parameters: dbproc  contains all information needed by db-lib to manage communications with the server. See also: DBROWS(), DBCMDROW(), dbnextrow(), dbresults(), DBROWTYPE().

STATUS dbrowtype (  DBPROCESS *  dbproc  )

Get returned row's type. For internal use only. Parameters: dbproc  contains all information needed by db-lib to manage communications with the server. See also: DBROWTYPE().

void dbsetavail (  DBPROCESS *  dbproc  )

Mark a DBPROCESS as "available". For internal use only. Parameters: dbproc  contains all information needed by db-lib to manage communications with the server. Remarks: Basically bogus. FreeTDS behaves the way Sybase's implementation does, but so what? Many db-lib functions set the DBPROCESS to "not available", but only dbsetavail() resets it to "available". See also: DBISAVAIL(). DBSETAVAIL().

RETCODE dbsetlbool (  LOGINREC *  login, int  value, int  which )

Set a boolean value in a LOGINREC structure. For internal use only. Called by various macros to populate login. Parameters: login  the LOGINREC* to modify. value  the value to set it to. which  the field to set. Remarks: Only DBSETBCP is implemented. Return values: SUCCEED  the value was set. FAIL  invalid value passed for which. Todo: DBSETNOSHORT, DBSETENCRYPT, DBSETLABELED

RETCODE dbsetllong (  LOGINREC *  login, long  value, int  which )

Set an integer value in a LOGINREC structure. For internal use only. Called by various macros to populate login. Parameters: login  the LOGINREC* to modify. value  the value to set it to. which  the field to set. Return values: SUCCEED  the value was set. FAIL  anything other than DBSETPACKET was passed for which.

RETCODE dbsetlname (  LOGINREC *  login, const char *  value, int  which )

Set the value of a string in a LOGINREC structure. For internal use only. Called by various macros to populate login. Parameters: login  the LOGINREC* to modify. value  the value to set it to. which  the field to set. Return values: SUCCEED  the value was set. FAIL  DBSETHID or other invalid which was tried.

RETCODE dbsetlshort (  LOGINREC *  login, int  value, int  which )

Set an integer value in a LOGINREC structure. For internal use only. Called by various macros to populate login. Parameters: login  the LOGINREC* to modify. value  the value to set it to. which  the field to set. Return values: SUCCEED  the value was set. FAIL  anything other than DBSETHIER was passed for which.

int dbtds (  DBPROCESS *  dbproc  )

Get the TDS version in use for dbproc. For internal use only. Parameters: dbproc  contains all information needed by db-lib to manage communications with the server. Returns: a DBTDS* token. Remarks: The integer values of the constants are counterintuitive. See also: DBTDS().

static int default_err_handler (  DBPROCESS *  dbproc, int  severity, int  dberr, int  oserr, char *  dberrstr, char *  oserrstr )  [static]

default error handler for db-lib (handles library-generated errors) For internal use only. The default error handler doesn't print anything. If you want to see your messages printed, install an error handler. If you think that should be an optional compile- or run-time default, submit a patch. It could be done. See also: DBDEAD(), dberrhandle().

DBPROCESS* tdsdbopen (  LOGINREC *  login, const char *  server, int  msdblib )

Form a connection with the server. For internal use only. Called by the dbopen() macro, normally. If FreeTDS was configured with --enable-msdblib, this function is called by (exported) dbopen() function. tdsdbopen is so-named to avoid namespace conflicts with other database libraries that use the same function name. Parameters: login  LOGINREC* carrying the account information. server  name of the dataserver to connect to. Returns: valid pointer on successful login. Return values: NULL  insufficient memory, unable to connect for any reason. See also: dbopen() Todo: use asprintf() to avoid buffer overflow. Todo: separate error messages for no-such-server and no-such-user.

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