◄Summary► ◄Example►                         ◄Up► ◄Contents► ◄Index► ◄Back►
─────Run-Time Library───────────────────────────────────────────────────────
 
     The _dos_keep routine installs terminate-and-stay-resident
     programs (TSRs) in memory, using system call 0x31.
 
     The routine first exits the calling process, leaving it in memory,
     and then returns the low-order byte of <retcode> to the parent of
     the calling process. Before returning execution to the parent
     process, _dos_keep sets the allocated memory for the now-resident
     process to <memsize> paragraphs. (A paragraph is 16 bytes.) Any
     excess memory is returned to the system.
 
     The _dos_keep function calls the same internal routines called by
     the exit functions. It therefore takes the following actions:
 
       1. Calls any functions that have been registered by atexit or
          _onexit calls.
 
       2. Flushes all file buffers.
 
       3. Restores interrupt vectors replaced by the startup code,
          primarily interrupt 0 (divide by zero). If the emulator math
          library is used and there is no coprocessor, interrupts
          0x34 through 0x3d are restored. If there is a coprocessor,
          interrupt 2 is restored.
 
     Do not use the emulator math library in TSRs unless you are
     familiar with the startup code and the coprocessor. Use the
     alternate math package if the TSR must do floating-point math.
 
     Do not run programs that use _dos_keep from inside the Microsoft
     Programmer's WorkBench environment, since doing so causes
     subsequent memory problems. The _dos_keep function terminates a
     program executed in the Programmer's WorkBench environment.
 
     Return Value
 
     None.
                                    -♦-