而在Linux中,使用struct flock结构体来实现文件锁功能。 在Linux系统中,struct flock结构体定义在头文件中,包含了文件锁的相关信息。该结构体包括了以下字段: - l_type:用于指定锁的类型,可以是F_RDLCK(共享读锁)、F_WRLCK(独占写锁)或者F_UNLCK(解锁)。 - l_whence:用于指定锁定起始位置,可以是SEEK_SET、SE...
}if((fd = open(argv[1], O_RDWR)) <0) sys_err("open");//f_lock.l_type = F_WRLCK; /*选用写琐*/f_lock.l_type = F_RDLCK;/*选用读琐*/f_lock.l_whence=SEEK_SET; f_lock.l_start=0; f_lock.l_len=0;/*0表示整个文件加锁*/fcntl(fd, F_SETLKW,&f_lock); printf("get f...
共享锁(F_RDLCK):允许多个进程读取文件,但不允许任何进程写入。 独占锁(F_WRLCK):只允许一个进程写入文件,且在写入期间不允许其他进程读取或写入。 解锁(F_UNLCK):释放之前设置的锁。 应用场景 并发控制:在多用户或多进程环境中,当多个实体需要访问同一文件时,使用文件锁来控制访问。
if (lock.l_type == F_RDLCK) (1分) else if (lock.l_type == F_WRLCK) (1分) lock.l_type = type; (1分) if ((fcntl(fd, F_SETLKW, &lock)) < 0) (1分) switch(lock.l_type) (1分) case F_RDLCK: (1分) case F_WRLCK: (1分) caseF_UNLCK: (1分) 反馈 收藏 ...
In the following example, assume thatrecwas assigned a value earlier in the exec: lock.l_len=40 lock.l_start=rec*40 lock.l_type=f_wrlck lock.l_whence=seek_set "f_getlk" fd "lock." if lock.l_type=f_unlck then /* lock is available for the requested 40 byte record */...
SCM s_f_rdlck; SCM s_f_wrlck; SCM s_f_unlck; SCM getlk_fcntl_lk_fdes(SCM s_fdes, SCM s_cmd, SCM s_list) { int rv; int fdes; struct flock lock; SCM l_type; SCM l_whence; SCM l_start; SCM l_len; SCM l_pid;
F_RDLCK: fcntl.LOCK_SH, fcntl.F_WRLCK: fcntl.LOCK_EX}[kw['l_type']] if cmd == fcntl.F_GETLK: return -errno.EOPNOTSUPP elif cmd == fcntl.F_SETLK: if op != fcntl.LOCK_UN: op |= fcntl.LOCK_NB elif cmd == fcntl.F_SETLKW: pass else: return -errno.EINVAL fcntl.lockf(self...
F_RDLCK Shared or read lock. This type of lock specifies that the process can read the locked part of the file, and other processes cannot write on that part of the file in the meantime. A process can change a held write lock, or any part of it, to a read lock, thereby making it...
RDLCK、F_WRLCK或F_UNLCK, 万一无法发生锁定,则归来-1 F_SETLKW 是F_SETLK的阻塞版本,在无法获得锁时会进去睡眠事态,万一能够获得锁可能捉拿到信号则归来 参数lock指针为flock构造指针定义如下 struct flock { ... short l_typejngaoy.com; short l_whence; off_t l_start; 锁定区域的开关位置 off_t l_...
F_RDLCK, 0, 0L, 0L, NOBLOCK},/* #4 Parent making a read lock on entire file */ {F_RDLCK, 0, 0L, 0L, SKIP, 0, 0L, 0L, /* Child attempting a write lock on entire file */ F_WRLCK, 0, 0L, 0L, WILLBLOCK},/* Test case: start boundary */ ...