Int 12/AX=FFFEh/CX=FFFEh

Back&Forth v1.62+ - API

AX = FFFEh
CX = FFFEh
BX = function
00h installation check
Return:
AX = 0001h installed
else  not loaded
01h (reserved)
02h build program ID list (shareware Back&Forth)
ES:DI -> buffer of at least 100 bytes, to be filled with words
Return:
AX = number of programs defined
ES:DI buffer filled with AX words
02h get memory statistics (Back&Forth Professional)
Return:
AX = available swap memory, KBytes
BX = maximum task size, KBytes
DX = fixed overhead per task, excluding video/macro
storage
03h switch to specified task (task need not be open yet)
DX = two-letter program ID
Return:
AX = status
0000h if task undefined
0001h task switch will occur when safe
04h (reserved)
05h (reserved)
06h get version (documented only for Back&Forth Professional)
Return:
AX = version * 100 (v1.71 = 00ABh)
07h spawn program (Back&Forth Professional only???)
ES:DI -> BF_SPAWN record (see #00232)
Return:
AX = status
0000h if no task handles free
0001h spawn will occur when safe
08h get open tasks (documented only for Back&Forth Professional)
ES:DI -> task info buffer (see #00231,#00233)
Return:
AX = number of open tasks (max 20)

Note: The supplied buffer must be large enough to hold 21 task entries 09h (reserved) ---Back&Forth Professional--- 0Ah get active clipboard filename

Return:
DX:AX -> ASCIZ clipboard filename
0Bh get active task number
AX = active task number (00h-13h)
BX = number of tasks allocated
DX = maximum number of tasks
0Ch (reserved)
0Dh (reserved)
0Eh (reserved)
0Fh stuff string into keyboard buffer
ES:DI -> ASCIZ string to be stuffed
Return:
Nothing
10h check if in graphics mode
Return:
AX = state
0000h color text mode
0004h mono text mode
FFFFh graphics mode
11h get Back&Forth Professional user number
Return:
AX = user number (0000h-00FFh)
12h switch task by task number
DX = task number
Return:
AX = status
0000h attempted to switch to active task
0001h task switch will occur when safe
FFFFh invalid task number
13h delete (kill) task
DX = task number
Return:
AX = status
0000h attempted to delete the active task
0001h successfully deleted
FFFFh invalid task number

Note: The active task number will change if the deleted task was lower in the task list than the active task 14h get next available task handle

Return:
AX = next available task handle FFFFh if task table is full

Program: Back & Forth is a task switcher by Progressive Solutions, Inc.

See Also: INT 11/AX=FFFEh

Index:
Installation check;BACK&FORTH

Format of Back&Forth task info buffer:

Offset  Size    Description     (Table 00231)
00h 21 BYTEs   ASCIZ task name
15h    BYTE    hotkey shift state (as for INT 16/AH=02h)
16h    WORD    hotkey scan code (see also #00006)
18h    WORD    program ID
Index:
Hotkeys;Back&Forth

See Also: #00232 - #00233

Format of Back&Forth Professional BF_SPAWN record: Offset Size Description (Table 00232) 00h 21 BYTEs task description

15h BYTE flag:
Disable hotkeys 16h WORD environment size in bytes 18h BYTE hotkey shift flags 19h WORD hotkey scancode 1Bh WORD maximum number of EMS pages 1Dh WORD required memory in KBytes 1Fh 3 BYTEs DESQview-style two-letter program ID 22h 13 BYTEs base name of program to be run (no path or extension) 2Fh 66 BYTEs directory from which to start program 71h 66 BYTEs initial current directory for program

See Also: #00231 - #00233

Format of Back&Forth Professional BF_TASK record: Offset Size Description (Table 00233) 00h DWORD Unix-style task start time (seconds since 1970/1/1) 04h 21 BYTEs task description 19h DWORD elapsed time in task (seconds) 1Dh WORD task ID 1Fh BYTE task hotkey keyboard flags 20h WORD task hotkey scan code (see also #00006) 22h DWORD time task was suspended/exited 26h WORD task handle

See Also: #00231 - #00232

Category: DOS-Based Task Switchers/Multitaskers - Int 12h - B

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