C++ 如何在C中引发处理自定义信号

我正在try 用C语言发出和处理定制信号.不幸的是，我只取得了部分成功.

我试着效仿这个例子:https://www.techonthenet.com/c_language/standard_library_functions/signal_h/raise.php

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

sig_atomic_t signaled = 0;

#define TEST_SIGNAL_50 50
#define TEST_SIGNAL_51 51
#define TEST_SIGNAL_52 52
#define SIGUSR1 50

void sigHandler(int sig)
{
    signaled = 1;

    //Switch statement to handle all signals
    switch(sig) {
        case TEST_SIGNAL_50:
            printf("Case 50 is Matched.\n");
            break;
        case TEST_SIGNAL_51:
            printf("Case 51 is Matched.\n");
            break;
        case TEST_SIGNAL_52:
            printf("Case 52 is Matched.\n");
            break;
        case SIGINT:
            printf("SIGINT Case is Matched.\n");
            break;
        default:    //Raised signal is not a match
            printf("Raised signal %d is not a match.\n", sig);
            break;

    }
}

int main() {
    printf("Hello, World! Test\n");
    
    int raiseResult;
    void (*prev_handler)(int);

    //Register the signal handler
    //prev_handler = signal(SIGINT, sigHandler);     //This works
    //prev_handler = signal(TEST_SIGNAL_50, sigHandler);
    prev_handler = signal(SIGUSR1, sigHandler);

    /* ... */
    //raiseResult = raise(SIGINT);                  //This works
    raiseResult = raise(SIGUSR1);
    /* ... */

    printf("raiseResult =%d.\n",raiseResult );
  
    printf("signaled =%d.\n",signaled);
  
    return 0;
}

最终目标是能够通过采取各种行动来处理不同的信号.但就目前而言，简单地点击Switch语句并获得相应的消息将是一种胜利.

我知道SIGINT是一个实际的信号.因此，当我筹集SIGINT的时候，sigHandler()就会起作用.但除此之外，我就不走运了.我从signal()得到的返回值是负值；这告诉我我的失败与signal()有关.

有没有人知道我用signal()做错了什么？