死活进不了子进程

[houzhenghui123]

最近在unix环境高级编程，在信号那一章节有一个练习题：
代码如下，代码进不了在注释，求原因，小菜在这里谢谢了

#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <signal.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
typedef void (*Sigfunc)(int);


/*****************************************
 *local var
 ****************************************/
static volatile sig_atomic_t sigflag;
static sigset_t newmask, oldmask, zeromask;

/******************************************
 *extern function declare 
 ******************************************/
Sigfunc signal(int signo, Sigfunc sigfun);
void TELL_WAIT(void);
void TELL_PARENT(pid_t pid);
void WAIT_PARENT(void);
void TELL_CHILD(pid_t pid);
void WAIT_CHILD(void);

/*****************************************
 *local function declare  and implement
 *****************************************/
static void sig_usr(int signo){
    sigflag = 1;
}
/******************************************
 *extern function implement 
 *****************************************/
void TELL_WAIT(void){
    if( signal(SIGUSR1, sig_usr) == SIG_ERR)
	;
    if( signal(SIGUSR2, sig_usr) == SIG_ERR)
	;
    sigemptyset(&zeromask);
    sigemptyset(&newmask);
    sigaddset(&newmask, SIGUSR1);
    sigaddset(&newmask, SIGUSR2);
    if(sigprocmask(SIG_BLOCK, &newmask, &oldmask)<0)
	;
}
void TELL_PARENT(pid_t pid){
    kill(pid, SIGUSR2);
}
void WAIT_PARENT(void){
    while(sigflag == 0)
	sigsuspend(&zeromask);
    sigflag = 0;
    if(sigprocmask(SIG_SETMASK, &oldmask, NULL)<0)
	;
}
void TELL_CHILD(pid_t pid){
    kill(pid, SIGUSR2);
}
void WAIT_CHILD(void){
    while(sigflag == 0)
	sigsuspend(&zeromask);
    sigflag = 0;
    if(sigprocmask(SIG_SETMASK, &oldmask, NULL)<0)
	;
}

Sigfunc signal(int signo, Sigfunc sigfun){
    struct sigaction act, oact;
    act.sa_handler = sigfun;
    sigemptyset(&act.sa_mask);
    act.sa_flags = 0;
    if(signo == SIGALRM){
#ifdef SA_INTERRUPT
	act.sa_flags |= SA_INTERRUPT;
	printf("[signal sysnc] defined SA_INTERRUPT\n");
#endif
    }else{
#ifdef SA_RESTART
	act.sa_flags |= SA_RESTART;
	printf("[Signal Sysnc] defined SA_RESTART\n");
#endif
    }
    if(sigaction(signo, &act, &oact)<0)
	return SIG_ERR;
    return oact.sa_handler;
}

static volatile int i = 0;
int main(void)
{
    pid_t pid;
    int fd;
    char buf[512];
    if((fd = open("./temp.file", O_CREAT | O_TRUNC | O_WRONLY, 0644))<0)
	;
    sprintf(buf, "%d", i);
    write(fd, buf , strlen(buf));
    if((pid = fork())<0){
	fprintf(stderr, "fork error\n");
	return -1;
    }else if(0 == pid){
	int j;
	printf("enter child\n");
	for(j = 0; j<100; j++){   ///死活都进不了这里////
	    WAIT_PARENT();
	    ++i;
	    sprintf(buf, "%d", i);
	    write(fd, buf , strlen(buf));
	    printf("child:%d\n", i);
	    TELL_PARENT(getppid());

	}
	exit(0);
    }else{
	printf("enter parent\n");
	TELL_CHILD(pid);
	while(i  != 100){
	    WAIT_CHILD();
	    ++i;
	    sprintf(buf, "%d", i);
	    write(fd, buf , strlen(buf));
	    printf("parent:%d\n", i);
	    TELL_CHILD(pid);
	}
    }
    return 0;
}

[帅得不敢出门]

#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <signal.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
typedef void (*Sigfunc)(int);


/*****************************************
 *local var
 ****************************************/
static volatile sig_atomic_t sigflag;
static sigset_t newmask, oldmask, zeromask;

/******************************************
 *extern function declare 
 ******************************************/
Sigfunc signal(int signo, Sigfunc sigfun);
void TELL_WAIT(void);
void TELL_PARENT(pid_t pid);
void WAIT_PARENT(void);
void TELL_CHILD(pid_t pid);
void WAIT_CHILD(void);

/*****************************************
 *local function declare  and implement
 *****************************************/
static void sig_usr(int signo){
    sigflag = 1;
}
/******************************************
 *extern function implement 
 *****************************************/
void TELL_WAIT(void){
    if( signal(SIGUSR1, sig_usr) == SIG_ERR)
    ;
    if( signal(SIGUSR2, sig_usr) == SIG_ERR)
    ;
    sigemptyset(&zeromask);
    sigemptyset(&newmask);
    sigaddset(&newmask, SIGUSR1);
    sigaddset(&newmask, SIGUSR2);
    if(sigprocmask(SIG_BLOCK, &newmask, &oldmask)<0)
    ;
}
void TELL_PARENT(pid_t pid){
    kill(pid, SIGUSR2);
}
void WAIT_PARENT(void){
    while(sigflag == 0)
    sigsuspend(&zeromask);
    sigflag = 0;
    if(sigprocmask(SIG_SETMASK, &oldmask, NULL)<0)
    ;
}
void TELL_CHILD(pid_t pid){
    kill(pid, SIGUSR2);
}
void WAIT_CHILD(void){
    while(sigflag == 0)
    sigsuspend(&zeromask);
    sigflag = 0;
    if(sigprocmask(SIG_SETMASK, &oldmask, NULL)<0)
    ;
}

Sigfunc signal(int signo, Sigfunc sigfun){
    struct sigaction act, oact;
    act.sa_handler = sigfun;
    sigemptyset(&act.sa_mask);
    act.sa_flags = 0;
    if(signo == SIGALRM){
#ifdef SA_INTERRUPT
    act.sa_flags |= SA_INTERRUPT;
    printf("[signal sysnc] defined SA_INTERRUPT\n");
#endif
    }else{
#ifdef SA_RESTART
    act.sa_flags |= SA_RESTART;
    printf("[Signal Sysnc] defined SA_RESTART\n");
#endif
    }
    if(sigaction(signo, &act, &oact)<0)
    return SIG_ERR;
    return oact.sa_handler;
}

static volatile int i = 0;
int main(void)
{
    pid_t pid;
    int fd;
    char buf[512];
    TELL_WAIT();
    if((fd = open("./temp.file", O_CREAT | O_TRUNC | O_WRONLY, 0644))<0)
    ;
    sprintf(buf, "%d", i);
    write(fd, buf , strlen(buf));
    if((pid = fork())<0){
    fprintf(stderr, "fork error\n");
    return -1;
    }else if(0 == pid){
    int j;
    printf("enter child\n");
    for(j = 0; j<100; j++){   ///死活都进不了这里////
        WAIT_PARENT();
        ++i;
        sprintf(buf, "%d", i);
        write(fd, buf , strlen(buf));
        printf("child:%d\n", i);
        TELL_PARENT(getppid());

    }
    exit(0);
    }else{
    printf("enter parent\n");
    TELL_CHILD(pid);
    while(i  != 100){
        WAIT_CHILD();
        ++i;
        sprintf(buf, "%d", i);
        write(fd, buf , strlen(buf));
        printf("parent:%d\n", i);
        TELL_CHILD(pid);
    }
    }
    return 0;
}

你原来的代码WAIT_CHILD(); 这里挂住了。

[houzhenghui123]

蛋疼，还有拼写错误
代码进不了在注释，求原因，小菜在这里谢谢了
->代码进不了在注释那个地方，求原因，小菜在这里谢谢了

[houzhenghui123]

最近up下！