set rcsid {$Id: capi3ref.tcl,v 1.36 2006/03/25 14:03:42 drh Exp $}
source common.tcl
header {C/C++ Interface For SQLite Version 3}
puts {
<h2>C/C++ Interface For SQLite Version 3</h2>
}

proc api {name prototype desc {notused x}} {
................................................................................
} {
 This routine identifies a callback function that might be invoked
 whenever an attempt is made to open a database table 
 that another thread or process has locked.
 If the busy callback is NULL, then SQLITE_BUSY is returned immediately
 upon encountering the lock.
 If the busy callback is not NULL, then the
 callback might invoked with two arguments.  The
 second argument is the number of prior calls to the busy callback
 for the same lock.  If the
 busy callback returns 0, then no additional attempts are made to
 access the database and SQLITE_BUSY is returned.
 If the callback returns non-zero, then another attempt is made to open the
 database for reading and the cycle repeats.

set rcsid {$Id: capi3ref.tcl,v 1.37 2006/04/05 01:02:08 drh Exp $}
source common.tcl
header {C/C++ Interface For SQLite Version 3}
puts {
<h2>C/C++ Interface For SQLite Version 3</h2>
}

proc api {name prototype desc {notused x}} {
................................................................................
} {
 This routine identifies a callback function that might be invoked
 whenever an attempt is made to open a database table 
 that another thread or process has locked.
 If the busy callback is NULL, then SQLITE_BUSY is returned immediately
 upon encountering the lock.
 If the busy callback is not NULL, then the
 callback will be invoked with two arguments.  The
 second argument is the number of prior calls to the busy callback
 for the same lock.  If the
 busy callback returns 0, then no additional attempts are made to
 access the database and SQLITE_BUSY is returned.
 If the callback returns non-zero, then another attempt is made to open the
 database for reading and the cycle repeats.

#
# Run this script to generated a faq.html output file
#
set rcsid {$Id: faq.tcl,v 1.35 2006/02/11 01:25:52 drh Exp $}
source common.tcl
header {SQLite Frequently Asked Questions</title>}

set cnt 1
proc faq {question answer} {
  set ::faq($::cnt) [list [string trim $question] [string trim $answer]]
  incr ::cnt
................................................................................
faq {
  Can multiple applications or multiple instances of the same
  application access a single database file at the same time?
} {
  <p>Multiple processes can have the same database open at the same
  time.  Multiple processes can be doing a SELECT
  at the same time.  But only one process can be making changes to
  the database at an given moement in time, however.</p>

  <p>SQLite uses reader/writer locks to control access to the database.
  (Under Win95/98/ME which lacks support for reader/writer locks, a
  probabilistic simulation is used instead.)
  But use caution: this locking mechanism might
  not work correctly if the database file is kept on an NFS filesystem.
  This is because fcntl() file locking is broken on many NFS implementations.

#
# Run this script to generated a faq.html output file
#
set rcsid {$Id: faq.tcl,v 1.36 2006/04/05 01:02:08 drh Exp $}
source common.tcl
header {SQLite Frequently Asked Questions</title>}

set cnt 1
proc faq {question answer} {
  set ::faq($::cnt) [list [string trim $question] [string trim $answer]]
  incr ::cnt
................................................................................
faq {
  Can multiple applications or multiple instances of the same
  application access a single database file at the same time?
} {
  <p>Multiple processes can have the same database open at the same
  time.  Multiple processes can be doing a SELECT
  at the same time.  But only one process can be making changes to
  the database at any moment in time, however.</p>

  <p>SQLite uses reader/writer locks to control access to the database.
  (Under Win95/98/ME which lacks support for reader/writer locks, a
  probabilistic simulation is used instead.)
  But use caution: this locking mechanism might
  not work correctly if the database file is kept on an NFS filesystem.
  This is because fcntl() file locking is broken on many NFS implementations.