DosHoldSignal

Bindings:  C, MASM 

This call temporarily disables or enables signal processing for the 
current process. 

 DosHoldSignal     (ActionCode) 
 

 ActionCode (USHORT) - input 
    Disables or enables signals intended for the current process. 

    Value     Definition 
    0         Signals are enabled 
    1         Signals are disabled. 

 rc (USHORT) - return 
    Return code descriptions are: 

    0         NO_ERROR 
    1         ERROR_INVALID_FUNCTION 
 
 Remarks 

 DosHoldSignal with ActionCode = 1 causes signal processing (except 
 central processing errors and numeric processor errors) to be postponed 
 until a DosHoldSignal with ActionCode = 0 is issued.  Any signals that 
 occur while processing is disabled are recognized, but not accepted until 
 signal recognition is enabled. 

 To allow for nesting of requests, a count of the number of outstanding 
 DosHoldSignal requests with ActionCode = 1 are maintained. 

 DosHoldSignal is used by library routines, subsystems, and similar code 
 that lock critical sections or temporarily reserve resources needed to 
 prevent a signal from terminating a task. A process can have only one 
 signal handling address for each signal. Dynalink routines should not 
 have a signal handler (which might override a handler established by a 
 calling process). 

 Signals can be held for a short period and should be released and 
 re-held, if necessary.  Their guidelines for proper use are similar to 
 hardware interrupt counterparts such as the CLI/STI instructions. 

 
 Family API Considerations 

 Some options operate differently in the DOS mode than in the OS/2 mode. 
  Therefore, the following restriction applies to DosHoldSignal when 
 coding for the DOS mode: 

 The only signal recognized in the DOS mode is SIGINTR (Ctrl-C) and 
 SIGBREAK. Only SIGINTR and SIGBREAK are turned off by this call.