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嵌入式数据库sqlite 3.5.9的文档

the application-defined function to be a copy the

<a href="../c3ref/value.html">unprotected sqlite3_value</a> object specified by the 2nd parameter.  The
sqlite3_result_value() interface makes a copy of the 
<a href="../c3ref/value.html">sqlite3_value</a>
so that 
<a href="../c3ref/value.html">sqlite3_value</a> specified in the parameter may change or
be deallocated after sqlite3_result_value() returns without harm.
A 
<a href="../c3ref/value.html">protected sqlite3_value</a> object may always be used where an

<a href="../c3ref/value.html">unprotected sqlite3_value</a> object is required, so either
kind of 
<a href="../c3ref/value.html">sqlite3_value</a> object can be used with this interface.</p>

<p>If these routines are called from within the different thread
than the one containing the application-defined function that recieved
the 
<a href="../c3ref/context.html">sqlite3_context</a> pointer, the results are undefined.</p>

<p><h3>Invariants:</h3>
<table border="0" cellpadding="5" cellspacing="0">
<tr><td valign="top">F16403</td> 
<td valign="top">
The default return value from any SQL function is NULL.</td></tr>
<tr><td valign="top">F16406</td> 
<td valign="top">
The 
<a href="../c3ref/result_blob.html">sqlite3_result_blob(C,V,N,D)</a> interface changes the
return value of function C to be a blob that is N bytes
in length and with content pointed to by V.</td></tr>
<tr><td valign="top">F16409</td> 
<td valign="top">
The 
<a href="../c3ref/result_blob.html">sqlite3_result_double(C,V)</a> interface changes the
return value of function C to be the floating point value V.</td></tr>
<tr><td valign="top">F16412</td> 
<td valign="top">
The 
<a href="../c3ref/result_blob.html">sqlite3_result_error(C,V,N)</a> interface changes the return
value of function C to be an exception with error code

<a href="../c3ref/c_abort.html">SQLITE_ERROR</a> and a UTF8 error message copied from V up to the
first zero byte or until N bytes are read if N is positive.</td></tr>
<tr><td valign="top">F16415</td> 
<td valign="top">
The 
<a href="../c3ref/result_blob.html">sqlite3_result_error16(C,V,N)</a> interface changes the return
value of function C to be an exception with error code

<a href="../c3ref/c_abort.html">SQLITE_ERROR</a> and a UTF16 native byte order error message
copied from V up to the first zero terminator or until N bytes
are read if N is positive.</td></tr>
<tr><td valign="top">F16418</td> 
<td valign="top">
The 
<a href="../c3ref/result_blob.html">sqlite3_result_error_toobig(C)</a> interface changes the return
value of the function C to be an exception with error code

<a href="../c3ref/c_abort.html">SQLITE_TOOBIG</a> and an appropriate error message.</td></tr>
<tr><td valign="top">F16421</td> 
<td valign="top">
The 
<a href="../c3ref/result_blob.html">sqlite3_result_error_nomem(C)</a> interface changes the return
value of the function C to be an exception with error code

<a href="../c3ref/c_abort.html">SQLITE_NOMEM</a> and an appropriate error message.</td></tr>
<tr><td valign="top">F16424</td> 
<td valign="top">
The 
<a href="../c3ref/result_blob.html">sqlite3_result_error_code(C,E)</a> interface changes the return
value of the function C to be an exception with error code E.
The error message text is unchanged.</td></tr>
<tr><td valign="top">F16427</td> 
<td valign="top">
The 
<a href="../c3ref/result_blob.html">sqlite3_result_int(C,V)</a> interface changes the
return value of function C to be the 32-bit integer value V.</td></tr>
<tr><td valign="top">F16430</td> 
<td valign="top">
The 
<a href="../c3ref/result_blob.html">sqlite3_result_int64(C,V)</a> interface changes the
return value of function C to be the 64-bit integer value V.</td></tr>
<tr><td valign="top">F16433</td> 
<td valign="top">
The 
<a href="../c3ref/result_blob.html">sqlite3_result_null(C)</a> interface changes the
return value of function C to be NULL.</td></tr>
<tr><td valign="top">F16436</td> 
<td valign="top">
The 
<a href="../c3ref/result_blob.html">sqlite3_result_text(C,V,N,D)</a> interface changes the
return value of function C to be the UTF8 string
V up to the first zero if N is negative
or the first N bytes of V if N is non-negative.</td></tr>
<tr><td valign="top">F16439</td> 
<td valign="top">
The 
<a href="../c3ref/result_blob.html">sqlite3_result_text16(C,V,N,D)</a> interface changes the
return value of function C to be the UTF16 native byte order
string V up to the first zero if N is
negative or the first N bytes of V if N is non-negative.</td></tr>
<tr><td valign="top">F16442</td> 
<td valign="top">
The 
<a href="../c3ref/result_blob.html">sqlite3_result_text16be(C,V,N,D)</a> interface changes the
return value of function C to be the UTF16 big-endian
string V up to the first zero if N is
is negative or the first N bytes or V if N is non-negative.</td></tr>
<tr><td valign="top">F16445</td> 
<td valign="top">
The 
<a href="../c3ref/result_blob.html">sqlite3_result_text16le(C,V,N,D)</a> interface changes the
return value of function C to be the UTF16 little-endian
string V up to the first zero if N is
negative or the first N bytes of V if N is non-negative.</td></tr>
<tr><td valign="top">F16448</td> 
<td valign="top">
The 
<a href="../c3ref/result_blob.html">sqlite3_result_value(C,V)</a> interface changes the
return value of function C to be 
<a href="../c3ref/value.html">unprotected sqlite3_value</a>
object V.</td></tr>
<tr><td valign="top">F16451</td> 
<td valign="top">
The 
<a href="../c3ref/result_blob.html">sqlite3_result_zeroblob(C,N)</a> interface changes the
return value of function C to be an N-byte blob of all zeros.</td></tr>
<tr><td valign="top">F16454</td> 
<td valign="top">
The 
<a href="../c3ref/result_blob.html">sqlite3_result_error()</a> and 
<a href="../c3ref/result_blob.html">sqlite3_result_error16()</a>
interfaces make a copy of their error message strings before
returning.</td></tr>
<tr><td valign="top">F16457</td> 
<td valign="top">
If the D destructor parameter to 
<a href="../c3ref/result_blob.html">sqlite3_result_blob(C,V,N,D)</a>,

<a href="../c3ref/result_blob.html">sqlite3_result_text(C,V,N,D)</a>, 
<a href="../c3ref/result_blob.html">sqlite3_result_text16(C,V,N,D)</a>,

<a href="../c3ref/result_blob.html">sqlite3_result_text16be(C,V,N,D)</a>, or

<a href="../c3ref/result_blob.html">sqlite3_result_text16le(C,V,N,D)</a> is the constant 
<a href="../c3ref/c_static.html">SQLITE_STATIC</a>
then no destructor is ever called on the pointer V and SQLite
assumes that V is immutable.</td></tr>
<tr><td valign="top">F16460</td> 
<td valign="top">
If the D destructor parameter to 
<a href="../c3ref/result_blob.html">sqlite3_result_blob(C,V,N,D)</a>,

<a href="../c3ref/result_blob.html">sqlite3_result_text(C,V,N,D)</a>, 
<a href="../c3ref/result_blob.html">sqlite3_result_text16(C,V,N,D)</a>,

<a href="../c3ref/result_blob.html">sqlite3_result_text16be(C,V,N,D)</a>, or

<a href="../c3ref/result_blob.html">sqlite3_result_text16le(C,V,N,D)</a> is the constant

<a href="../c3ref/c_static.html">SQLITE_TRANSIENT</a> then the interfaces makes a copy of the
content of V and retains the copy.</td></tr>
<tr><td valign="top">F16463</td> 
<td valign="top">
If the D destructor parameter to 
<a href="../c3ref/result_blob.html">sqlite3_result_blob(C,V,N,D)</a>,

<a href="../c3ref/result_blob.html">sqlite3_result_text(C,V,N,D)</a>, 
<a href="../c3ref/result_blob.html">sqlite3_result_text16(C,V,N,D)</a>,

<a href="../c3ref/result_blob.html">sqlite3_result_text16be(C,V,N,D)</a>, or

<a href="../c3ref/result_blob.html">sqlite3_result_text16le(C,V,N,D)</a> is some value other than
the constants 
<a href="../c3ref/c_static.html">SQLITE_STATIC</a> and 
<a href="../c3ref/c_static.html">SQLITE_TRANSIENT</a> then
SQLite will invoke the destructor D with V as its only argument
when it has finished with the V value.</td></tr>
</table>
</p>
<p>See also lists of
  <a href="objlist.html">Objects</a>,
  <a href="constlist.html">Constants</a>, and
  <a href="funclist.html">Functions</a>.</p>
<hr><small><i>
This page last modified 2008/05/12 13:08:44 UTC
</i></small></div></body></html>