Documentation Source Text

  to the built-in [date and time functions].
}

COMPILE_OPTION {HAVE_MALLOC_USABLE_SIZE} {
  If the HAVE_MALLOC_USABLE_SIZE option is true, then SQLite tries uses the
  malloc_usable_size() interface to find the size of a memory allocation obtained
  from the standard-library malloc() or realloc() routines.  This option is only
  applicable if the standard-library malloc() is used.  On Apple systems,
  "zone malloc" is used instead, and so this option is not applicable.  And, of
  course, if the application supplies its own malloc implementation using
  [SQLITE_CONFIG_MALLOC] then this option has no effect.
  <p>
  If the HAVE_MALLOC_USABLE_SIZE option is omitted or is false, then SQLite 
  uses a wrapper around system malloc() and realloc() that enlarges each allocation
  by 8 bytes and writes the size of the allocation in the initial 8 bytes, and

</p>

<p>If any of these options are defined, then the same set of SQLITE_OMIT_*
options must also be defined when using the 'lemon' tool to generate the
parse.c file and when compiling the 'mkkeywordhash' tool which generates 
the keywordhash.h file.
Because of this, these options may only be used when the library is built
from canonical source, not from the [amalgamation].

Some SQLITE_OMIT_* options might work, or appear to work, when used with
the [amalgamation].  But this is not guaranteed.  In general, always compile
from canonical sources in order to take advantage of SQLITE_OMIT_* options.
</p>

<blockquote>
<i><b>Important Note:</b> The SQLITE_OMIT_* options may not work with the
[amalgamation].  SQLITE_OMIT_* compile-time
options usually work correctly only when SQLite is built from canonical 
source files.
</i>
</blockquote>


<p>Special versions of the SQLite amalgamation that do work with a
predetermined set of SQLITE_OMIT_* options can be generated.  To do so,
make a copy of the Makefile.linux-gcc makefile template in the canonical
source code distribution.  Change the name of your copy to simply "Makefile".
Then edit "Makefile" to set up appropriate compile-time options.  Then
type:
<blockquote><tt>make clean; make sqlite3.c</tt></blockquote>
The resulting "sqlite3.c" amalgamation code file (and its associated
header file "sqlite3.h") can then be moved to a non-unix platform
for final compilation using a native compiler.</p>

<p>The SQLITE_OMIT_* options are unsupported.  By this we mean that
an SQLITE_OMIT_* option that omits code from the build in the current
release might become a no-op in the next release.  Or the other way around:
an SQLITE_OMIT_* that is a no-op in the current release might cause code
to be excluded in the next release.  Also, not all SQLITE_OMIT_* options
are tested.  Some SQLITE_OMIT_* options might cause SQLite to malfunction
and/or provide incorrect answers.

<blockquote>
<i><b>Important Note:</b>
The SQLITE_OMIT_* compile-time options are unsupported.
</i></blockquote>









<tcl>
COMPILE_OPTION {SQLITE_OMIT_ALTERTABLE} {
  When this option is defined, the 
  [ALTER TABLE] command is not included in the 
  library. Executing an [ALTER TABLE] statement causes a parse error.
}

}
doc {Foreign Key Support} {foreignkeys.html} {
  This document describes the support for foreign key constraints introduced
  in version 3.6.19.
}
doc {Full Text Search} {fts3.html} {
  A description of the SQLite Full Text Search (FTS3) extension.
}
doc {Indexes On Expressions} {expridx.html} {
  Notes on how to create indexes on expressions instead of just
  individual columns.
}
doc {Internal versus External Blob Storage} {intern-v-extern-blob.html} {
  Should you store large BLOBs directly in the database, or store them
  in files and just record the filename in the database?  This document
  seeks to shed light on that question.
}
doc {Limits In SQLite} {limits.html} {