<h1>WSERV</h1>

<p>

The window server runs continuously and brings the machine down if it

crashes, so it cannot panic its own thread when it detects an error in one of

its client’s requests. Instead it panics the client’s thread using

<code class="ApiItem">CSession::Panic()</code>. These panics have a category of WSERV. 

</p>

<p>

These panics are defined in the enumeration <code>TClientPanic</code> in

<code class="filename">w32cmd.h</code>. 

</p>

<p>

Note that some panics are raised in debug builds only. 

</p>

<code>1</code>

<p>

Out of range opcode. 

</p>

<p>

The client has sent a request opcode that wasn’t recognised. Each

server-side object can only handle some of the requests defined in the window

server, and if the request isn’t recognised, this panic is raised. 

</p>

<p>

Clients would normally only get this is if they bypass the normal

Window Server API. 

</p>

<code>2</code>

<p>

Invalid command buffer. 

</p>

<p>

A corrupt buffer of requests was discovered by the server. This is

raised when the buffer itself is noticeably broken, and not when the commands

in it are wrong. 

</p>

<code>3</code>

<p>

Invalid handle. 

</p>

<p>

The server couldn’t find the target object for a request in the

handle index. This can be raised when a command is sent to the handle for a

window that has been closed, for example. 

</p>

<code>4</code>

<p>

A handle whose value was NULL was detected. 

</p>

<p>

For example, when Constructing one of the subclasses of the

client-side <a href="../reference-cpp/WSERV8.1/RWindowBaseClass.html#%3a%3aRWindowBase" title="class RWindowBase"><code class="ApiItem">RWindowBase</code></a> with a client handle argument of

NULL. 

</p>

<p>

On the server side, a <code>TWsClCmdCreateWindow</code> with a

client handle field of <code>NULL</code> passed as argument to

<code>CWsClientWindow::ConstructL()</code> will raise this error. 

</p>

<code>5</code>

<p>

A single drawing command was too big to fit into the

<a href="../../guide/Graphics-subsystem-guide/WindowServerClientSide/WindowServerGuide1/ClientSideBuffer.guide.html#WindowServerGuide6%2eClientSideBuffer">client-side buffer</a>. 

</p>

<p>

The size of the buffer may be increased. See

<a href="../reference-cpp/WSERV8.1/RWsSessionClass.html#%3a%3aRWsSession%3a%3aSetBufferSizeL%28%29" title="function RWsSession::SetBufferSizeL()"><code class="ApiItem">RWsSession::SetBufferSizeL()</code></a> and

<a href="../reference-cpp/WSERV8.1/RWsSessionClass.html#%3a%3aRWsSession%3a%3aSetMaxBufferSizeL%28%29" title="function RWsSession::SetMaxBufferSizeL()"><code class="ApiItem">RWsSession::SetMaxBufferSizeL()</code></a>. 

</p>

<code>6</code>

<p>

Invalid window handle. 

</p>

<p>

A handle which should have referred to a window of a particular

type referred to a window of another type, or the object index didn’t recognise

the handle. 

</p>

<p>

On the server side, this panic is ultimately raised by

<code>CWsClient::HandleToWindow()</code> and

<code>CWsClient::HandleToClientWindow()</code> during handle conversions. 

</p>

<code>7</code>

<p>

Invalid bitmap handle. 

</p>

<p>

A corrupt bitmap handle was encountered. This is a common panic

uncovered when a bitmap handle refers to nothing, or to a server-side object

that isn’t a bitmap. 

</p>

<p>

Also: 

</p>

<p>

In response to an <code>EWsGcOpUseBrushPattern</code> request

if the bitmap parameter couldn’t be used. On the client side,

<a href="../reference-cpp/WSERV8.1/CWindowGcClass.html#%3a%3aCWindowGc%3a%3aUseBrushPattern%28%29" title="function CWindowGc::UseBrushPattern()"><code class="ApiItem">CWindowGc::UseBrushPattern()</code></a> sends this request. 

</p>

<p>

In response to an <code>EWsSpriteOpAppendMember</code> request

when the bitmaps for the sprite member can't be created on the server side. On

the client side, <a href="../reference-cpp/WSERV8.1/RWsSpriteBaseClass.html#%3a%3aRWsSpriteBase%3a%3aAppendMember%28%29" title="function RWsSpriteBase::AppendMember()"><code class="ApiItem">RWsSpriteBase::AppendMember()</code></a> sends this

request. 

</p>

<p>

Any failed attempt to duplicate a supplied bitmap. 

</p>

<code>8</code>

<p>

Event read already outstanding. 

</p>

<p>

<a href="../reference-cpp/WSERV8.1/RWsSessionClass.html#%3a%3aRWsSession%3a%3aEventReady%28%29" title="function RWsSession::EventReady()"><code class="ApiItem">RWsSession::EventReady()</code></a>,

<a href="../reference-cpp/WSERV8.1/RWsSessionClass.html#%3a%3aRWsSession%3a%3aRedrawReady%28%29" title="function RWsSession::RedrawReady()"><code class="ApiItem">RWsSession::RedrawReady()</code></a>, or

<a href="../reference-cpp/WSERV8.1/RWsSessionClass.html#%3a%3aRWsSession%3a%3aPriorityKeyReady%28%29" title="function RWsSession::PriorityKeyReady()"><code class="ApiItem">RWsSession::PriorityKeyReady()</code></a> was called again when an

event read was already outstanding, i.e.. when an event was waiting to be

delivered by the window server. 

</p>

<code>9</code>

<p>

Attempted to use a non-active graphics context. 

</p>

<p>

A drawing request was sent to a graphics context when the context

was not active. 

</p>

<p>

On the server side, this panic is raised by

<code>CWsGc::CommandL()</code> on all requests received when the context isn&#8217;t

active except <code>EWsGcOpActivate</code>, <code>EWsGcOpDeactivate</code>,

<code>EWsGcOpFree</code>, and <code>EWsGcOpTestInvariant</code>. 

</p>

<code>10</code>

<p>

Attempted to activate an already active graphics context. 

</p>

<p>

On the server side, this is raised by

<code>CWsGc::Activate()</code> as a response to a <code>EWsGcOpActivate

</code>

request. 

</p>

<p>

The request is sent by the client-side method

<a href="../reference-cpp/WSERV8.1/CWindowGcClass.html#%3a%3aCWindowGc%3a%3aActivate%28%29" title="function CWindowGc::Activate()"><code class="ApiItem">CWindowGc::Activate()</code></a>. 

</p>

<code>11</code>

<p>

Window already active. 

</p>

<p>

An attempt was made to reactivate an active window. The request is

sent by the client-side method <a href="../reference-cpp/WSERV8.1/RWindowBaseClass.html#%3a%3aRWindowBase%3a%3aActivate%28%29" title="function RWindowBase::Activate()"><code class="ApiItem">RWindowBase::Activate()</code></a>. 

</p>

<p>

On the server side, this panic is raised by

<code>CWsClientWindow::Activate()</code> in response to an

<code>EWsWinOpActivate</code> request. 

</p>

<code>12</code>

<p>

Already inside a begin/end redraw pair. 

</p>

<p>

A begin-redraw window request was made when the window had already

begun redrawing. Begin-redraw messages are paired with end-redraw messages, and

ordering is important. Invoking <a href="../reference-cpp/WSERV8.1/RWindowClass.html#%3a%3aRWindow%3a%3aBeginRedraw%28%29" title="function RWindow::BeginRedraw()"><code class="ApiItem">RWindow::BeginRedraw()</code></a>,

then <code>RWindow::BeginRedraw()</code> again before the corresponding

<a href="../reference-cpp/WSERV8.1/RWindowClass.html#%3a%3aRWindow%3a%3aEndRedraw%28%29" title="function RWindow::EndRedraw()"><code class="ApiItem">RWindow::EndRedraw()</code></a> raises this panic. 

</p>

<p>

On the server side, this panic is raised if an

<code>EWsWinOpBeginRedraw</code> request is sent twice before the closing

<code>EWsWinOpEndRedraw

</code>. 

</p>

<code>13</code>

<p>

Invalid font handle. 

</p>

<p>

On the client-side is raised if

<a href="../reference-cpp/WSERV8.1/CWindowGcClass.html#%3a%3aCWindowGc%3a%3aUseFont%28%29" title="function CWindowGc::UseFont()"><code class="ApiItem">CWindowGc::UseFont()</code></a> is called with an invalid font

handle. 

</p>

<p>

On the server side, <code>CWsGc::SetGcAttribute()</code> raises

this error in response to an <code>EWsGcOpUseFont</code> request. 

</p>

<code>14</code>

<p>

Printing with no active font. 

</p>

<p>

A command to draw text to a window was sent to a graphics context

when no font was set. Any of the overloads of

<a href="../reference-cpp/WSERV8.1/CWindowGcClass.html#%3a%3aCWindowGc%3a%3aDrawTextVertical%28%29" title="function CWindowGc::DrawTextVertical()"><code class="ApiItem">CWindowGc::DrawTextVertical()</code></a> or

<a href="../reference-cpp/WSERV8.1/CWindowGcClass.html#%3a%3aCWindowGc%3a%3aDrawText%28%29" title="function CWindowGc::DrawText()"><code class="ApiItem">CWindowGc::DrawText()</code></a> might cause the panic to be raised;

the font should be set using <a href="../reference-cpp/WSERV8.1/CWindowGcClass.html#%3a%3aCWindowGc%3a%3aUseFont%28%29" title="function CWindowGc::UseFont()"><code class="ApiItem">CWindowGc::UseFont()</code></a> first. 

</p>

<p>

On the server side, this panic is raised by

<code>CWsGc::DoDrawCommand()</code> in response to any of the requests to

display text defined in <code>TWsGcOpcodes</code>. 

</p>

<code>15</code>

<p>

Attempted to set an invalid text cursor type, see

<a href="../reference-cpp/WSERV8.1/RWindowGroupClass.html#%3a%3aRWindowGroup%3a%3aSetTextCursor%28%29" title="function RWindowGroup::SetTextCursor()"><code class="ApiItem">RWindowGroup::SetTextCursor()</code></a>. 

</p>

<p>

Valid types are defined in the <a href="../reference-cpp/WSERV8.1/TTextCursorStruct.html#%3a%3aTTextCursor" title="struct TTextCursor"><code class="ApiItem">TTextCursor</code></a>

struct. 

</p>

<code>16</code>

<p>

A drawing command was sent to a graphics context active on a group

window. 

</p>

<code>17</code>

<p>

Not used. 

</p>

<code>18</code>

<p>

Not used. 

</p>

<code>19</code>

<p>

Attempted to use a patterned brush when the pattern bitmap has not

yet been set&#0160;&#8212;  <code>UseBrushPattern()</code>. 

</p>

<code>20</code>

<p>

Not used. 

</p>

<code>21</code>

<p>

Attempted to do a client destroy function on an illegal handle. 

</p>

<p>

A client tried to destroy or cancel a server-side object by its

handle on an unrecognised handle, or on a handle of the wrong type for the

operation. 

</p>

<p>

This panic may be caused by the

<a href="../reference-cpp/WSERV8.1/RWindowGroupClass.html#%3a%3aRWindowGroup%3a%3aCancelCaptureKeyUpAndDowns%28%29" title="function RWindowGroup::CancelCaptureKeyUpAndDowns()"><code class="ApiItem">RWindowGroup::CancelCaptureKeyUpAndDowns()</code></a> or

<a href="../reference-cpp/WSERV8.1/RWindowGroupClass.html#%3a%3aRWindowGroup%3a%3aCancelCaptureKey%28%29" title="function RWindowGroup::CancelCaptureKey()"><code class="ApiItem">RWindowGroup::CancelCaptureKey()</code></a> methods. These correspond

to the <code>EWsWinOpCancelCaptureKeyUpsAndDowns</code> and

<code>EWsWinOpCancelCaptureKey</code> server requests. In this case, the panic

means that there is no such capture key object in existence in the target

window group. 

</p>

<code>22</code>

<p>

Panic from the Anim DLL. 

</p>

<p>

An animation DLL tried either changing its default or next timing

interval when its timing mode was set to <code>ESyncNone</code>, or activating

a graphics context when the context was already activated. 

</p>

<p>

There are a variety of other reasons why this panic might be

raised, all which are Anim DLL related. The Animation writer can also cause

functions raise this panic. 

</p>

<code>23</code>

<p>

Invalid Anim object handle. 

</p>

<p>

A null animation handle was detected in the server on receipt of an

animation command, possibly because the relevant animation has been deleted.

This panic may be raised by a subclass of <a href="../reference-cpp/WSERV8.1/RAnimClass.html#%3a%3aRAnim" title="class RAnim"><code class="ApiItem">RAnim</code></a> calling

<a href="../reference-cpp/WSERV8.1/RAnimClass.html#%3a%3aRAnim%3a%3aCommand%28%29" title="function RAnim::Command()"><code class="ApiItem">RAnim::Command()</code></a> or

<a href="../reference-cpp/WSERV8.1/RAnimClass.html#%3a%3aRAnim%3a%3aCommandReply%28%29" title="function RAnim::CommandReply()"><code class="ApiItem">RAnim::CommandReply()</code></a>. 

</p>

<p>

On the server side, the <code>EWsAnimDllOpCommandReply</code> and

<code>EWsAnimDllOpCommand</code> requests can raise this panic in

<code>CWsAnimDll

</code>. 

</p>

<code>24</code>

<p>

Leave from a non-leaving animation function. 

</p>

<p>

Code in an animated DLL called by the server invoked

<code>Leave()</code>. Animated DLL code is provided by the client and run by

the server, so unhandled leaves are trapped and the notification is passed on

as a client panic. 

</p>

<code>25</code>

<p>

Not used. 

</p>

<code>26</code>

<p>

Not used. 

</p>

<code>27</code>

<p>

Not used. 

</p>

<code>28</code>

<p>

Inconsistent polygon or polyline data was supplied. For example

when restarting without finishing an old polygon. 

</p>

<code>29</code>

<p>

A client attempted to set a negative shadow height. 

</p>

<p>

This panic is caused by a call to

<a href="../reference-cpp/WSERV8.1/RWindowBaseClass.html#%3a%3aRWindowBase%3a%3aSetShadowHeight%28%29" title="function RWindowBase::SetShadowHeight()"><code class="ApiItem">RWindowBase::SetShadowHeight()</code></a> with a negative argument. 

</p>

<p>

On the server side, <code>CWsClientWindow::CommandL()</code> raises

the panic in response to an invalid <code>EWsWinOpSetShadowHeight</code>

request. 

</p>

<code>30</code>

<p>

Not used. 

</p>

<code>31</code>

<p>

The client tried to construct a window with an invalid redraw type.

The valid redraw types defined in the enumeration <code>TWinTypes</code> of

<code class="filename">w32cmd.h

</code>. 

</p>

<p>

On the server side, this panic is raised by

<code>CWsClientWindow::ConstructL()</code> in response to an initialisation

message containing an invalid redraw type. 

</p>

<code>32</code>

<p>

A server-side redraw region is almost certainly corrupt. 

</p>

<p>

This panic is raised when an <code>EWsWinOpGetInvalidRegion</code>

is received by a <code>CWsRedrawMsgWindow</code> with a <code>TInt</code>

parameter of zero or less. 

</p>

<code>33</code>

<p>

The client failed to provide a reply buffer to a server-side

function when one was needed. 

</p>

<p>

All server-side functions that need more space for their reply than

a <code>TInt</code> use the client&#8217;s reply buffer. If the client fails to

provide space for such replies, this panic will be emitted. 

</p>

<p>

This panic is raised by <code>CWsClient::ReplyBuf()</code> when

<code>CWsClient</code>&#8217;s reply buffer is null. 

</p>

<code>34</code>

<p>

Not used. 

</p>

<code>35</code>

<p>

A client passed an invalid or unrecognised corner type or flag. 

</p>

<p>

This panic is raised in response to a client call to

<a href="../reference-cpp/WSERV8.1/RWindowBaseClass.html#%3a%3aRWindowBase%3a%3aSetCornerType%28%29" title="function RWindowBase::SetCornerType()"><code class="ApiItem">RWindowBase::SetCornerType()</code></a> when specifying inconsistent

or non-existent flags. 

</p>

<p>

Valid flags are masked by <a href="../reference-cpp/WSERV8.1/TCornerTypeEnum.html#%3a%3aECornerTypeMask" title="field ECornerTypeMask"><code class="ApiItem">ECornerTypeMask</code></a>, and

recognised types are defined in <a href="../reference-cpp/WSERV8.1/TCornerTypeEnum.html#%3a%3aTCornerType" title="enum TCornerType"><code class="ApiItem">TCornerType</code></a>. These are all

defined in <code class="filename">w32std.h</code>. 

</p>

<p>

The server raises this panic as a response to

<code>EWsWinOpSetCornerType</code> request with an undefined corner type or an

unrecognised flag in its parameters. 

</p>

<code>36</code>

<p>

The server was asked to update a region of a backed-up window which

has not had MaintainBackup called on it. 

</p>

<p>

A client-side call to either form of

<a href="../reference-cpp/WSERV8.1/RBackedUpWindowClass.html#%3a%3aRBackedUpWindow%3a%3aUpdateScreen%28%29" title="function RBackedUpWindow::UpdateScreen()"><code class="ApiItem">RBackedUpWindow::UpdateScreen()</code></a> may raise this panic. 

</p>

<p>

On the server side, the panic is raised in response to an

<code>EWsWinOpUpdateScreenRegion</code> or <code>EWsWinOpUpdateScreen

</code>

request when not maintaining a full backup of a backed-up window. 

</p>

<code>37</code>

<p>

Panic raised when it was not possible to read or write data to the

client thread. The data is usually contained in a descriptor. 

</p>

<code>38</code>

<p>

The client attempted to access a sprite after the sprite's window

was destroyed. Note that pointer cursors are implemented as sprites. 

</p>

<code>39</code>

<p>

A client requested event data without having received an event

telling it that the data was ready. 

</p>

<code>40</code>

<p>

The mask for a sprite is smaller than the sprite’s bitmap. A mask

is permitted to be larger than its bitmap. 

</p>

<code>41</code>

<p>

Bad sprite handle. 

</p>

<p>

A null sprite handle was encountered, or a handle which was

supposed to refer to a sprite referred to something else. 

</p>

<p>

The client-side methods

<a href="../reference-cpp/WSERV8.1/RWindowTreeNodeClass.html#%3a%3aRWindowTreeNode%3a%3aSetCustomPointerCursor%28%29" title="function RWindowTreeNode::SetCustomPointerCursor()"><code class="ApiItem">RWindowTreeNode::SetCustomPointerCursor()</code></a> and

<a href="../reference-cpp/WSERV8.1/RWsSessionClass.html#%3a%3aRWsSession%3a%3aSetSystemPointerCursor%28%29" title="function RWsSession::SetSystemPointerCursor()"><code class="ApiItem">RWsSession::SetSystemPointerCursor()</code></a>, amongst others, can

cause this panic to be raised; they correspond to the server requests

<code>EWsWinOpSetCustomPointerCursor</code> and

<code>EWsClOpSetSystemPointerCursor</code>. 

</p>

<code>42</code>

<p>

A client attempted to set or clear a system pointer cursor without

first owning the list of system pointer cursors. 

</p>

<p>

<a href="../reference-cpp/WSERV8.1/RWsSessionClass.html#%3a%3aRWsSession%3a%3aSetSystemPointerCursor%28%29" title="function RWsSession::SetSystemPointerCursor()"><code class="ApiItem">RWsSession::SetSystemPointerCursor()</code></a> and

<a href="../reference-cpp/WSERV8.1/RWsSessionClass.html#%3a%3aRWsSession%3a%3aClearSystemPointerCursor%28%29" title="function RWsSession::ClearSystemPointerCursor()"><code class="ApiItem">RWsSession::ClearSystemPointerCursor()</code></a> can raise this

panic. See also <a href="../reference-cpp/WSERV8.1/RWsSessionClass.html#%3a%3aRWsSession%3a%3aClaimSystemPointerCursorList%28%29" title="function RWsSession::ClaimSystemPointerCursorList()"><code class="ApiItem">RWsSession::ClaimSystemPointerCursorList()</code></a>

and <a href="../reference-cpp/WSERV8.1/RWsSessionClass.html#%3a%3aRWsSession%3a%3aFreeSystemPointerCursorList%28%29" title="function RWsSession::FreeSystemPointerCursorList()"><code class="ApiItem">RWsSession::FreeSystemPointerCursorList()</code></a>. 

</p>

<p>

The server requests which can raise this panic are

<code>EWsClOpSetSystemPointerCursor</code> and

<code>EWsClOpClearSystemPointerCursor</code>. 

</p>

<code>43</code>

<p>

A client attempted to enable a pointer move buffer when none was

allocated. 

</p>

<p>

<a href="../reference-cpp/WSERV8.1/RWindowBaseClass.html#%3a%3aRWindowBase%3a%3aEnablePointerMoveBuffer%28%29" title="function RWindowBase::EnablePointerMoveBuffer()"><code class="ApiItem">RWindowBase::EnablePointerMoveBuffer()</code></a> can

cause this panic to be emitted; the corresponding server request is

<code>EWsWinOpEnablePointerMoveBuffer</code>. 

</p>

<code>44</code>

<p>

Raised in response to commands that send a string, when the string

has been incorrectly stored in the command buffer. 

</p>

<code>45</code>

<p>

Not used. 

</p>

<code>46</code>

<p>

An invalid call or request parameter was detected by

<code>CWsPassword</code>. This can be caused: 

</p>

<p>

By <a href="../reference-cpp/WSERV8.1/RWindowBaseClass.html#%3a%3aRWindowBase%3a%3aPasswordWindow%28%29" title="function RWindowBase::PasswordWindow()"><code class="ApiItem">RWindowBase::PasswordWindow()</code></a> sending

an <code>EWsWinOpPasswordWindow</code> server request whose password mode

parameter is not recognised. 

</p>

<p>

By an attempt to cancel the password window by a client which

doesn’t own the window. 

</p>

<p>

By <a href="../reference-cpp/WSERV8.1/RWsSessionClass.html#%3a%3aRWsSession%3a%3aPasswordEntered%28%29" title="function RWsSession::PasswordEntered()"><code class="ApiItem">RWsSession::PasswordEntered()</code></a> sending a

<code>EWsClOpPasswordEntered</code> server request when no password window has

been set, or when the client does not own the password window. 

</p>

<p>

Valid password modes are defined in

<a href="../reference-cpp/WSERV8.1/TPasswordModeEnum.html#%3a%3aTPasswordMode" title="enum TPasswordMode"><code class="ApiItem">TPasswordMode</code></a> of <code class="filename">w32std.h</code>. 

</p>

<code>47</code>

<p>

An invalid compute mode was sent to the window server. On the

client side, <a href="../reference-cpp/WSERV8.1/RWsSessionClass.html#%3a%3aRWsSession%3a%3aComputeMode%28%29" title="function RWsSession::ComputeMode()"><code class="ApiItem">RWsSession::ComputeMode()</code></a> can do this, the

window server request is <code>EWsClOpComputeMode</code>. Valid compute modes

are defined in the enumeration <a href="../reference-cpp/WSERV8.1/RWsSessionClass.html#%3a%3aRWsSession%3a%3aTComputeMode" title="enum RWsSession::TComputeMode"><code class="ApiItem">RWsSession::TComputeMode</code></a>,

which is declared in <code class="filename">w32std.h</code>. 

</p>

<code>48</code>

<p>

A client attempted to set the display mode of a backed-up window.

This can be done with

<a href="../reference-cpp/WSERV8.1/RWindowBaseClass.html#%3a%3aRWindowBase%3a%3aSetRequiredDisplayMode%28%29" title="function RWindowBase::SetRequiredDisplayMode()"><code class="ApiItem">RWindowBase::SetRequiredDisplayMode()</code></a> or the

<code>EWsWinOpRequiredDisplayMode</code> server request. 

</p>

<code>49</code>

<p>

A client attempted to get a message when has not been signalled in

the server. 

</p>

<p>

This panic can be raised on a client thread calling

<code class="ApiItem">RWindowGroup::FetchMessage()</code> or sending the

<code>EWsWinOpGetMessageSize</code> or <code>EWsWinOpGetMessage

</code> messages. 

</p>

<code>50</code>

<p>

A client tried to send a second initialisation message, i.e. to

call <a href="../reference-cpp/WSERV8.1/RWsSessionClass.html#%3a%3aRWsSession%3a%3aConnect%28%29" title="function RWsSession::Connect()"><code class="ApiItem">RWsSession::Connect()</code></a> twice. 

</p>