APUE，死锁发生时内核的策略
这个例子是APUE 程序清单14-4.#include "apue.h"#include<fcntl.h>
#include "TELL_WAIT.c"
#include "lock_reg.c"
static void lockabyte(const char *name,pid_t pid,int fd,off_t offset){
if(writew_lock(fd,offset,SEEK_SET,1) <0)
printf("%s :writew_lock error\n",name);
printf("%s-%d :got the lock ,byte %ld\n",name ,pid,offset);
}
int main(void){
int fd;
pid_t pid;
if((fd=creat("templock",FILE_MODE)) <0)
printf("create error\n");
if(write(fd,"abc",3) !=3)
printf("write to file error\n");
TELL_WAIT();
if((pid=fork()) <0){
printf("fork error\n");
}else if(pid==0){
lockabyte("child",getpid(),fd,0);
TELL_PARENT(getppid());
WAIT_PARENT();
lockabyte("child",getpid(),fd,1);
}else{
lockabyte("parent",getpid(),fd,1);
TELL_CHILD(pid);
WAIT_CHILD();
lockabyte("parent",getpid(),fd,0);
}
exit(0);
}
为什么运行结果是：
parent-3269 :got the lock ,byte 1
child-3270 :got the lock ,byte 0
parent :writew_lock error
parent-3269 :got the lock ,byte 0
child-3270 :got the lock ,byte 1
内核把死锁解决了？？
页:
[1]