INT 15 - DESQview v2.50+ - SEND MESSAGE WITH ERROR RECOVERY
AH = 12h
BH = 80h
Note:   this function is identical to AH=12h/BH=00h, except that DESQview will
not pop up a "Programming Error" window, instead returning an error
code in AL:
00h no error
01h invalid values
02h alias invalid
03h handle valid but wrong type
04h invalid handle

See also: 1512

1512 - DESQview v2.50+ - SEND MESSAGE WITH ERROR RECOVERY