backtrace跟踪错误

#include <execinfo.h>
#include <iostream>
#include <signal.h>

void map_dump(void) {
char buff[64] = {0x00};
sprintf(buff, "cat /proc/%d/maps", getpid());
system((const char *)buff);
}

// 打印堆栈信息
void trace_dump(void) {
int j, nptrs;

void *buffer[100];
char **strings;

#define SIZE 1024
nptrs = backtrace(buffer, SIZE);
printf("backtrace() returned %d addresses\n", nptrs);

/* The call backtrace_symbols_fd(buffer, nptrs, STDOUT_FILENO)
would produce similar output to the following: */

strings = backtrace_symbols(buffer, nptrs);
if (strings == NULL) {
perror("backtrace_symbols");
exit(EXIT_FAILURE);
}

for (j = 0; j < nptrs; j++)
printf("%s\n", strings[j]);

free(strings);
}

void signal_handler(int signo) {

map_dump();
printf("\n=========>>>catch signal %d <<<=========\n", signo);
printf("Dump stack start...\n");
trace_dump();
printf("Dump stack end...\n");
signal(signo, SIG_DFL); /* 恢复信号默认处理 */
raise(signo); /* 重新发送信号 */
}

void trigger_crash() {
int *p = nullptr;
*p = 0;
}

int main(int argc, char *argv[]) {

signal(SIGSEGV, signal_handler);
signal(SIGABRT, signal_handler);
signal(SIGINT, signal_handler);

trigger_crash();

// done:
return 0;
}