INT 21 - European MS-DOS 4.0 - "PBLOCK" - BLOCK A PROCESS AH = 99h DS:BX -> memory location to block on CX = timeout in milliseconds DH = nonzero if interruptable Return: CF clear if awakened by event AX = 0000h CF set if unusual wakeup ZF set if timeout, clear if interrupted by signal AX = nonzero Desc: suspend calling process until another process sends a "restart" signal or a timeout occurs SeeAlso: AH=9Ah,INT 2F/AX=0802h