Print stacktraces in C

print_trace.c

// from http://stackoverflow.com/a/4732119/1846480 and adapted from a comment to not require sudo
// It's also needed to pass the -ggdb. For instance gcc source.c -o target.o -w -ggdb

#include <sys/prctl.h>

void print_trace() {
  char pid_buf[30];
  sprintf(pid_buf, "%d", getpid());
  char name_buf[512];
  name_buf[readlink("/proc/self/exe", name_buf, 511)]=0;
  prctl(PR_SET_PTRACER, PR_SET_PTRACER_ANY, 0, 0, 0);
  int child_pid = fork();
  if (!child_pid) {
    dup2(2,1); // redirect output to stderr
    fprintf(stdout,"stack trace for %s pid=%s\n",name_buf,pid_buf);
    execlp("gdb", "gdb", "--batch", "-n", "-ex", "thread", "-ex", "bt", name_buf, pid_buf, NULL);
    abort(); /* If gdb failed to start */
  } else {
    waitpid(child_pid,NULL,0);
  }
}