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API Details In order for you to get a feel for the power built-in to each and every DESQview, we've included a short description about each API command. The DESQview 2.2 API is an objected-oriented interface. The data structures DESQview uses to represent windows, mailboxes, etc. are called "objects". A call to the API involves "sending a message" to an object, indicating which of several operations you want performed on that data structure. This is referred to as the "send interface". Almost the entire API consists of sending one of 34 messages to one of 7 different object types. The DESQview 2.2 API also has a non-object-oriented interface called the "direct call interface". This is the small subset of API functions that are not, by nature, object oriented or that are convenient alternatives to the send interface. The DESQview 2.2 API has a concise way of encoding a complete description of a window so that a single call to the API can create the window, fill it with the desired information, size and position it on the display, and define fields that interact with the user. All this is done using "Window Streams". So that you can interrogate a window for its current contents, position, etc., the DESQview 2.2 API also has "Query Streams". In fact, any window parameter that can be set by a Window Stream can be read by a Query Stream. DESQview calls the portion of itself that interfaces with the user the "Window Manager". Each time a user presses the DESQ key (normally the Alt key) and makes a menu selection, it is the Window Manager that opens, switches, rearranges and closes windows, transfers data, displays help, or quits DESQview. In order for an application to have the same power as the user, the DESQview 2.2 API has "Manager Streams". Manager Streams enable an application to interact with the Window Manager. Using Manager Streams an application can, for example, ask the Window Manager to make one of its windows the topmost window in the system, disallow any resizing of the window by the user, and even notify the application if the user tries to close the window. Using Manager Streams an application can disallow use of the DESQview menu and DESQview submenus. But, there's still even more to the DESQview 2.2 API. DESQview provides a comprehensive set of functions for simplifying the job of interfacing with the user. Instead of dealing with user input a single character at a time, your application can present entire menus, dialogue boxes, help screens to DESQview and get back the resulting user input. Common functions such as cursor control, insertion and deletion of characters, tracking the mouse, and selection from option lists are performed by DESQview. DESQview performs these functions under control of a data structure called the "Field Table". Information about a window's size, position, contents and Field Table can be combined together into "Panels". Panels can be stored on disk or in memory for later display. Panels can be constructed manually or via the DESQview API Panel Design Tool. DESQview 2.2 API Commands: Send Interface Commands WINDOW Objects ADDTO write characters &attributes to a window AT position the logical cursor EOF return TRUE if cursor is past end window ERASE clear a window FREE close and free a window or a task HANDLE return handle of current task's window LEN return # characters/line in logical window NEW create a new window or task OPEN fill a window with a given character READ read the next logical line from a window READN read the next n characters/attributes REDRAW redraw a window SIZEOF return total # characters/logical window SUBFROM write attributes to a window WRITE write characters and/or command streams KEYBOARD Objects ADDTO set keyboard control flags CLOSE close a keyboard object ERASE discard all input queued to Keyboard FREE free a Keyboard object GETFLAGS get keyboard control flags GETPRI get objectq priority level of keyboard HANDLE return handle of task's default keybd NEW create a new Keyboard object OPEN attach a Keyboard to a window READ get the next input from the Keyboard SETESC intercept keystrokes to input fields SETFLAGS replace keyboard control flags SETPRI set objectq priority level of keyboard SIZEOF return # of input buffers queued STATUS get the scan code for the last key read SUBFROM clear keyboard control flags WRITE add input buffer to Keyboard queue MAILBOX Objects ADDR return tender of the last message READ ADDTO send a message and status by value CLOSE close a Mailbox ERASE discard all queued messages FREE frees a Mailbox GETFLAGS get mailbox control flags GETPRI get objectq priority level of mailbox HANDLE return handle of task's default mailbox LOCK request exclusive access to a resource NEW create a new Mailbox OPEN open a Mailbox for input READ get the next message from the queue SETFLAGS replace mailbox control flags SETPRI set objectq priority level of mailbox SETNAME assign a name to a Mailbox SIZEOF return the # of messages in the queue STATUS return status of the last message READ SUBFROM send a message &status by reference WRITE send a message by value with status=0 OBJECTQ Objects CLOSE Close an Objectq ERASE remove all objects from the queue HANDLE return the handle of a task's Objectq OPEN open the Objectq READ wait for input from any open object SIZEOF return the number of objects queued STATUS return whether or not Objectq is open SUBFROM remove specific object from queue WRITE add an object to the Objectq PANEL Objects APPLY display a particular panel CLOSE close a panel object DIR return a pointer to the panel directory FREE free a panel object NEW create a panel object OPEN associate panel object with a panel file SIZEOF return the # of panels in a panel file STATUS verify success of an OPEN or APPLY POINTER Objects ADDTO set pointer control flags CLOSE stop taking pointer input ERASE discard all pointer messages FREE free a Pointer object GETFLAGS get pointer control flags GETPRI get objectq priority level of pointer GETSCALE return the current scaling factors NEW create a new Pointer object OPEN start taking Pointer input for window READ wait for the next pointer message SETFLAGS replace pointer control flags SETPRI set objectq priority level of pointer SETSCALE set the current scaling factors SIZEOF return the number of messages queued STATUS return the status of the last message SUBFROM reset pointer control flags WRITE move the pointer to a specified position TIMER Objects ADDTO start a timer for a specified interval CLOSE close a Timer object ERASE cancel the current timer interval FREE free a Timer object GETPRI get objectq priority level of timer LEN return time remaining before expiration NEW create a new Timer object OPEN open a Timer object READ wait for the current timer to expire SETPRI set objectq priority level of timer SIZEOF return elapsed time since timer started STATUS return the status of the Timer object WRITE start a timer to end at a specified time Direct Call Interface Commands APILEVEL define minimum API level required APPNUM get the current application's number ASSERTMAP get current mapping context and set new one BEGINC begin critical region CSTYLE use C language style control codes DBGPOKE poke debug information onto display DISPEROR display an error message window DVPRESENT determine if DESQview is present ENDC end critical region FINDMAIL find a mailbox by name FREEBIT undefine second-level interrupt handler GETBIT define a second-level interrupt handler GETBUF get address of a Logical Window Buffer GETCRIT get critical region nesting level GETERROR get error handling level of current task GETMEM allocate buffer from System Memory ISOBJ determine if a handle is valid JUSTIFY turn off/on automatic justification KMOUSE control the keyboard mouse LOCATE find window at given screen location NEWPROC start a new process OBJTYPE determine the object type of a given handle OSTACK switch to task's internal stack PAUSE relinquish control to other tasks PGMINT interrupt another task POSTTASK awaken task by posting its Objectq POSWIN position a window on the display PRINTC display a character in a window PUSHKEY push key into keyboard input stream PUTMEM free a buffer allocated by GETMEM SETBIT schedule a second-level interrupt handler SETERROR set error handling level of current task SHADOW get window buffer and start shadowing SOUND make a sound START start a task that was previously stopped STOP stop a task until START is called UPDATE update a portion of a window USTACK switch off task's internal stack Window Stream Commands 00 to 9F print strings (attributes,characters,blanks) to window A0 to CF change size/ position of a window D0 to DF set options for appearance of window: frames, color, show/hide window, display of control characters E0 to EF perform immediate actions: clearing, scrolling, recoloring, redrawing window; create new windows &repeat command sequences F0 to FF define, read, write fields within window. Query Stream Commands same as Window Stream commands Manager Streams 00 to 3F Allows specific DESQview commands: move & resize window, scroll data, hide, rearrange program, suspend application, display DESQview menu 40 to 71 notify application on specific DESQview commands. 84 to 8B specify environment of window: suspend application when it is in background, set application's asynchronous notification. AC to BF enable/disable DESQview extensions. C0 to FF reorder, hide, unhide, suspend resume applications.