Guardian Native C Library Calls Reference Manual (G06.29+, H06.08+, J06.03+)

Guardian Native C Library Calls (s) signal(3)
NAME
signal - Specifies the action to take upon delivery of a signal
LIBRARY
G-series native Guardian processes: system library
G-series native OSS processes: system library
H-series and J-series native Guardian processes: implicit libraries
H-series and J-series OSS processes: implicit libraries
32-bit H-series and J-series OSS processes that use the POSIX User Thread Model library:
/G/system/zdllnnn/zputdll
64-bit H-series and J-series OSS processes that use the POSIX User Thread Model library:
/G/system/zdllnnn/yputdll.PP
SYNOPSIS
#include <signal.h>
void (*signal(
int signal,
void (*function)(int))) (int);
PARAMETERS
signal Specifies the signal. The signal names are defined in the signal.h header file.
The range of valid signals depends on the requested action.
The signal() function does not support the SIGUNCP signal.
function Specifies the action to be taken upon receipt of the signal identified by the signal
parameter.
DESCRIPTION
The signal() function allows the calling process to change the action to be taken when a specific
signal is delivered to the process issuing this function call.
Associated with every signal is a signal-dependent default action. The signal() function can
change this action by causing the receiving process to
• Ignore the delivery of a specific signal.
• Restore the default action for a specific signal.
• Invoke a signal-catching function (that is, "catch" the signal) to execute in response to
the delivery of a specific signal.
If a signal-catching function is installed using the signal() function, then the action is restored to
the default action each time the signal is delivered. Note that this action is different from the
action taken by the sigaction() function.
See the signal(4) reference page for the defined signal names and details about the cause and
default action of each defined signal.
Use From the Guardian Environment
If signal() is called in a code module compiled in the Guardian environment and called from a
TNS or accelerated Guardian process (main() was compiled with systype guardian), the
signal-catching function found in the Guardian registry is entered. (The default signal-catching
function is identified by the SIG_DFL value for signal action.) If the signal specified by the sig-
nal parameter is unknown, the value -1 is returned and errno is set to [EINVAL].
If signal() is called in a code module compiled in the Guardian environment and called from a
G-series TNS or accelerated OSS process (main() was compiled with systype oss), the
signal-catching function found in the Guardian registry is entered. (The default signal-catching
527192-018 Hewlett-Packard Company 6−39