signal.h

• raise
• signal

raise

Header

signal.h

Prototype

int raise(int sig);

Description

raise issues a signal to the executing program. The signal type, sig, is discussed in the signal description. When the signal is raised by the raise function call, the current signal-handling routine will be called. See signal() for a complete description.

Return Value

Returns 0 if successful, otherwise returns a non-zero value.

Compatibility

DOS Windows 3.x Phar Lap DOSX Win32

See Also

signal

Example

/* 	Example for raise
	Also demonstrates signal 
*/ 

#include <signal.h>
#include <stdio.h>
#include <stdlib.h>

void div_zero (int val)
{   
   printf("Divide by zero detected!\n");
   exit(EXIT_FAILURE); 
} 

int main()
{   
   float numerator = 3.0F, denominator = 0.0F; 

   if (signal(SIGFPE, div_zero) == SIG_ERR)
   {   
      perror ("Could not set signal SIGFPR");
      abort (); 
   } 

   if (denominator == 0.0F)
       raise(SIGFPE); 
   else
       printf("The result of the division is %g\n",
	    numerator / denominator);
   return EXIT_SUCCESS;
}

Output

Divide by zero detected! 

signal

Header

signal.h

Prototype

void (* signal(int sig, void (__cdecl *handler)(int)))(int);

Description

signal allows a program to define how signals from the operating system are handled. Argument sig must be one of these constants:

Constant	Description
NSIG	The number of signals
SIGABRT	Abnormal termination
SIGBREAK	Control-break
SIGFPE	Floating-point error
SIGILL	Illegal instruction
SIGINT	Interrupt
SIGSEGV	Segment violation
SIGTERM	Terminate (CTRL+ C)

The following macros are special values for handler:

Macro	Description
SIG_DFL	Handled in the default manner.
SIG_IGN	Ignored the signal.

signal sets the response. handler must be declared with C linkage. When a signal occurs, the signal's behavior is reset to SIG_DFL, the function for signal is called and sig is passed to it.

Return Value

Returns the previous value of handler. A return value of SIG_ERR indicates an error and errno is set.

Compatibility

DOS Windows 3.x Phar Lap DOSX Win32

See Also

raise