[问题]一些头文件和函数的问题

[luchen]

请问<errno.h>的作用；<fcntl.h>的作用
函数strerror(errno)的作用（最好详细点）

[dbzhang800]

man strerror
自己看看

[奇诺]

引用自APUE2

3.14. fcntl Function
The fcntl function can change the properties of a file that is already open.

The fcntl function is used for five different purposes.
1、Duplicate an existing descriptor (cmd = F_DUPFD)
2、Get/set file descriptor flags (cmd = F_GETFD or F_SETFD)
3、Get/set file status flags (cmd = F_GETFL or F_SETFL)
4、Get/set asynchronous I/O ownership (cmd = F_GETOWN or F_SETOWN)
5、Get/set record locks (cmd = F_GETLK, F_SETLK, or F_SETLKW)