Test program for re-enterancy of signal handlers. Compile with 'gcc -o signal signal.c' (or adjust to taste).

signals.c

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

void
handler(int signum)
{
   printf("Catching signal %d\n",signum);
   sleep(1);
   printf("Done handling %d\n", signum);
}

int main()
{
   // Register signal and signal handler
   signal(SIGINT, handler);
   signal(SIGQUIT, handler);

   while(1)
   {
      printf("Doing meaningful work\n")
      pause();
   }
   return EXIT_SUCCESS;
}

transcript.txt

: cez@rhk; ./a.out 
Program processing stuff here.
^CCaught signal 2
Exit signal handler for 2
Program processing stuff here.
^\Caught signal 3
Exit signal handler for 3
Program processing stuff here.
^CCaught signal 2
^\Caught signal 3
Exit signal handler for 3
Exit signal handler for 2
Program processing stuff here.
^\Caught signal 3
^CCaught signal 2
Exit signal handler for 2
Exit signal handler for 3
Program processing stuff here.
^Z
zsh: suspended  ./a.out
: cez@rhk; kill %./a.out
: cez@rhk; 
[1]  + terminated  ./a.out
: cez@rhk; fg