c SIGINT表现如何？

Question

I'm experimenting with SIGINT. I basically want my program to start as soon as the user hits control-c. When this happens, I'm going to then get the program to make a pipe.

Now, I decided that when control-c is pressed in the signal handler it will call a function to create the pipe. Yet this is messing up. It's fine running a printf command but refuses to carry out the if statement until you press control-c again. Anyone able to assist?

Realistically, I want to disable control-C after it has been pressed once.

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

void catchme(int signal);
void Setup();


int main()
{
  if (signal(SIGINT, catchme) == SIG_ERR)
  {
    write(2, "Error catching signal C\n", 26);
  } 

  printf("To begin, please press CTRL + C\n");
  for(;;);
  return 0;
}

void catchme(int signal)
{
  write(1, "\n Caught Signal from Control C\n", 33);
  Setup();
}

void Setup()
{
  int firstPipe[2];

  printf("Lets set up...\n");

  if (pipe(firstPipe) < 0)
  {
    printf("Error creating pipe 1\n");
    //abort program
  }
  else
  {
    printf("working so far");
  }
}

Answer 1

You should get a debugger working. It would provide you with the answer to your question within seconds, and it's essential for trying to track down these kinds of problems. What seems very mystifying and unclear, when you're trying to interpret the output, will seem very easy when you're stepping through it, and you can see everything.

This will probably lead to pipe() not doing what you expect, you'll check errno, and presumably get a useful answer.

The commenter's advise about avoiding doing stuff in signal handlers is good, as it's not portable. However, most modern OSs are quite permissive, so I'm not sure if that's your problem in this case.