函数key(lkey1=ftok("/etc/profile",1)里的第二个参数项目ID具体是指什么含义
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解决时间 2021-11-19 15:04
- 提问者网友：十年饮冰
- 2021-11-19 07:23
函数key(lkey1=ftok("/etc/profile",1)里的第二个参数项目ID具体是指什么含义
最佳答案
- 五星知识达人网友：渡鹤影
- 2021-11-19 08:30
DESCRIPTION
The ftok() function uses the identity of the file named by the given pathname (which must refer to an existing, accessible file) and the least signifi-
cant 8 bits of proj_id (which must be non-zero) to generate a key_t type System V IPC key, suitable for use with msgget(2), semget(2), or shmget(2).
The resulting value is the same for all pathnames that name the same file, when the same value of proj_id is used. The value returned should be differ-
ent when the (simultaneously existing) files or the project IDs differ.
大概意思是根据前面字符串和后面的字节固定那么返回结果就固定，任何一个值不同返回都可能不同，但无论如何不能保证返回的KEY在系统中没有被使用。
The ftok() function uses the identity of the file named by the given pathname (which must refer to an existing, accessible file) and the least signifi-
cant 8 bits of proj_id (which must be non-zero) to generate a key_t type System V IPC key, suitable for use with msgget(2), semget(2), or shmget(2).
The resulting value is the same for all pathnames that name the same file, when the same value of proj_id is used. The value returned should be differ-
ent when the (simultaneously existing) files or the project IDs differ.
大概意思是根据前面字符串和后面的字节固定那么返回结果就固定，任何一个值不同返回都可能不同，但无论如何不能保证返回的KEY在系统中没有被使用。
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