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  1. #include <iostream>
  2.  
  3. #include <stdio.h>
  4. #include <stdlib.h>
  5. #include <signal.h>
  6. #include <time.h>
  7. #include <errno.h>
  8. #include <assert.h>
  9.  
  10. #include <unistd.h>
  11. #include <sys/time.h>
  12.  
  13. static int alarm_pipe[2];
  14.  
  15. extern "C" {
  16.     static int xsignal (int sig, void (*handler)(int))
  17.     {
  18.         struct sigaction sa;
  19.         sa.sa_handler = handler;
  20.         sigemptyset(&sa.sa_mask);
  21.         sa.sa_flags = 0;
  22.         return sigaction(sig, &sa, NULL);
  23.     }
  24.  
  25.     void sigalarm_handler (int)
  26.     {
  27.         if (write(alarm_pipe[1], "", 1) != 1) {
  28.             char msg[] = "write: failed from sigalarm_handler\n";
  29.             write(2, msg, sizeof(msg)-1);
  30.             abort();
  31.         }
  32.     }
  33. }
  34.  
  35. int main ()
  36. {
  37.     if (pipe(alarm_pipe) != 0) {
  38.         perror("pipe");
  39.         exit(EXIT_FAILURE);
  40.     }
  41.  
  42.     if (xsignal(SIGALRM, sigalarm_handler) != 0) {
  43.         perror("sigaction");
  44.         exit(EXIT_FAILURE);
  45.     }
  46.  
  47.     struct itimerval it = { { 0, 200000 }, { 0, 200000 } };
  48.     if (setitimer(ITIMER_REAL, &it, 0) != 0) {
  49.         perror("setitimer");
  50.         exit(EXIT_FAILURE);
  51.     }
  52.  
  53.     char c;
  54.     struct timeval tv;
  55.     for (int i = 0; i < 10; ++i) {
  56.         for (;;) {
  57.             ssize_t alarm_pipe_read_result = read(alarm_pipe[0], &c, 1);
  58.             if ((alarm_pipe_read_result < 0) && (errno == EINTR)) continue;
  59.             assert(alarm_pipe_read_result == 1);
  60.             break;
  61.         }
  62.         //... do sampling ...
  63.         gettimeofday(&tv, 0);
  64.         std::cerr << tv.tv_usec/1000 << std::endl;
  65.     }
  66. }
  67.  
Success #stdin #stdout 0s 2848KB
comments (?)
stdin 
Standard input is empty
stdout 
Standard output is empty
https://ideone.com/zEc2nV
language:
C++ (gcc 8.3)
created:
12 years ago
visibility:
public

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