C语言 signal和raise和sprintf函数使用

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

//void (*signal(int sig, void (*func)(int)))(int)
static void  signal_handler(int signo)
{
    printf("signal handler is \n");

}

int main()
{

    /**
        kill把信号发送给进程或进程组;
        raise把信号发送给(进程)自身.
    **/
    int ret = -1;
    char buf[510] = {0};
    signal(SIGILL,signal_handler);
    getchar();
    ret = raise(SIGILL);  // 自己给自己发信号   kill 向pid发信号
    printf("ret is %d\n",ret);
    //free(&ret);
    sprintf(buf, "_G711u");
    printf("buf is %s\n",buf);
    sprintf(buf, ".wav");
    printf("buf is %s\n",buf);

    while(1);
    return 0;
}