问为什么SIGINT被发送到子进程而不执行任何操作？

EN

pid_t childid;

void catch_sigint(int sig)
{
    signal(SIGINT,SIG_DFL);
    kill(childid,sig);
}

int debuger (char *address, parm *vars)
{
    int ignore=1;
    int status;

    childid = fork();
    signal(SIGINT,catch_sigint);
    if(childid==0)
    {
        ptrace(PTRACE_TRACEME,0, NULL,NULL);
        if(execve(address,NULL,NULL)==-1)
        {
            perror("ERROR occured when trying to create program to trace\n");
            exit(1);
        }
    }
    else
    {
        int f_time=1;

        while(1)
        {
            long system_call;

            wait(&status);
            if(WIFEXITED(status))break;
            if(WIFSIGNALED(status))break;

            system_call = ptrace(PTRACE_PEEKUSER,childid, 4 * ORIG_EAX, NULL);

            if(!strcmp(vars->category,"process-control") || !strcmp(vars->category,"all"))      
                ignore = pr_calls(system_call,ignore,limit,childid,vars->mode); //function that takes the system call that is made and prints info about it
            if(!strcmp(vars->category,"file-management") || !strcmp(vars->category,"all"))
                ignore = fl_calls(system_call,ignore,limit,childid,vars->mode);

            if(f_time){ignore=1;f_time=0;}
            ptrace(PTRACE_SYSCALL,childid, NULL, NULL);
        }        
    }
    signal(SIGINT,SIG_DFL);
    return 0;
}

#include <stdio.h>

int main(void)
{
    for(;;) printf("HELLO WORLD\n");        
    return 0;
}