Open System Services System Calls Reference Manual (G06.25+, H06.03+)

signal(4) OSS System Calls Reference Manual
NAME
signal - Contains definitions and variables used by signal functions
SYNOPSIS
#include <signal.h>
DESCRIPTION
The signal.h header file contains:
• Declarations of symbolic constants used to refer to the signals that occur in the OSS
environment.
• Declarations for the sigset_t type and the sigaction structure. Note that G-series TNS or
accelerated processes and all native processes use different declarations for sigset_t; all
processes using the same sigset_t declaration must be of the same process type.
• Declarations of additional symbolic constants used in signal handling:
SA_NOCLDSTOP
Indicates that the SIGCHLD signal should not be generated when a
child process stops.
SIG_ABORT Requests that the process terminate abnormally when a specific signal is
received.
SIG_DEBUG Requests that the process enter the debugger when a specific signal is
received.
SIG_DFL Requests default signal handling.
SIG_ERR Indicates an error condition by reserving a return code for a certain class
of functions. Such functions return a pointer to a function that takes an
integer as a parameter and returns void.
SIG_IGN Requests that signals be ignored.
• Declarations of additional symbolic constants used by the sigprocmask() function for
handling process signal masks:
SIG_BLOCK Requests a union of the current mask and a supplied value.
SIG_SETMASK
Creates a mask from the supplied value.
SIG_UNBLOCK
Requests a mask of the current mask less the supplied value.
Signal Generation and Delivery
A signal is said to be generated for (or sent to) a process when the event that causes the signal
first occurs. Examples of such events include detection of hardware faults, timer expiration, and
any operating system trap condition normally detectable by a TNS or accelerated Guardian pro-
cess, in addition to terminal activity, or the invocation of the kill() function.
Note: Signals cannot be sent to a TNS or accelerated Guardian process.
Each process has an action to be taken in response to each signal defined by the system. A signal
is said to be delivered to a process when the appropriate action for the process and signal is
taken.
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