sigvec - Provide a compatibility interface to the sigaction()
function
#include <sys/signal.h>
int sigvec(
int signal,
struct sigvec *in_vec,
struct sigvec *out_vec );
Specifies the signal number. Points to a sigvec structure
that specifies the action to be taken when the specified
signal is delivered, the mask to be used when calling the
signal handler, and the flags that modify signal behavior.
Points to a sigvec structure that is set to the previous
signal action state on successful return from the sigvec()
function.
The sigvec() function is provided for compatibility with
old UNIX systems; its function is a subset of the operations
available with the sigaction() function. Like the
sigaction() function, the sigvec() function allows the
user to set the action to take upon the receipt of a signal
and to specify a signal handler mask to block signals
before calling the signal handler. However, only signals
with values 1 to 31 can be masked on entry to a signalhandler
set up with the sigvec() function.
The sigvec structure has the following members:
void (*sv_handler)(); int sv_mask; int sv_flags;
The sv_handler field specifies the action for the signal,
and can be SIG_DFL, SIG_IGN, or the address of a signal
handler function. See the sigaction() function for a
detailed description of the signal actions.
The sv_mask field specifies a mask which specifies signals
to block (in addition to any signals already blocked at
time of delivery) when the signal handler function is
called for the signal. Signal i is blocked if the i-th
bit of the mask is set. Only signals with values 1 to 31
can be masked with the sigvec() function. The sv_flags
field contains flags that further specify signal behavior.
If SV_ONSTACK is set, the signal handler runs on the signal
stack specified by the sigstack() function; otherwise,
the signal handler runs on the stack of the process
receiving the signal. If SV_INTERRUPT is set, a system
call that is interrupted by signal returns a value of -1
with errno set to [EINTR]; otherwise, a system call interrupted
by signal is restarted.
If the value of the in_vec parameter is a null pointer,
then the signal handler information is not set. If the
value of the out_vec parameter is null, then the previous
signal handler information is not returned.
Once a signal handler is assigned, it remains assigned
until another call to sigvec() is made or a call is made
to signal(), sigaction() or one of the exec functions.
The sigvec() function is provided for compatibility only,
and its use is not recommended. Programs should use the
sigaction() function instead.
The sigvec() function does not check the validity of the
sv_handler field pointer. If it points to a location outside
of the process address space, the process receives a
memory fault when the system attempts to call the signal
handler. If the sv_handler field points to anything other
than a function, the results are unpredictable.
The signal-handler function can be declared as follows:
void handler (
int signal );
Upon successful completion, a value of 0 (zero) is
returned. If the sigvec() function fails, a value of -1 is
returned and errno is set to indicate the error.
If the sigvec() function fails, no new signal handler is
installed and errno may be set to one of the following
values: The in_vec or out_vec parameter points to a location
outside of the process' address space. The signal
parameter is not a valid signal number or an attempt was
made to ignore or supply a handler for the SIGKILL signal.
Functions: kill(2), ptrace(2), sigaction(2), sigblock(2),
sigpause(3), sigstack(2)
sigvec(2)
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