《UNIX环境高级编程》第2版 读书笔记一 ——文件I/O

STDIN_FILENO(0)、STDOUT_FILENO(1)、STDERR_FILENO(2)

#include

(1)   int open(const char *pathname, int oflag, /*mode_t mode */);

                                                 若成功则返回文件描述符，若出错则返回-1

oflag:     O_RDONLY、O_WRONLY、O_RDWR

              O_APPEND、O_TRUNC、O_NOCTTY、O_NONBLOCK

              O_CREAT(mode_t)、O_EXCL、O_SYNC

int creat(const char *pathname, mode_t mode);

                                                 若成功则返回文件描述符，若出错则返回-1

       等效：open(pathname, O_WRONLY | O_CREAT | O_TRUNC, mode)

#include

(2)   int close(int filedes);                                                          

                                                 若成功则返回0，若出错则返回-1

(3)   off_t lseek(int fd, off_t offset, int whence)

                                                 若成功则返回新的文件偏移量，若出错则返回-1

Whence:              SEEK_SET、SEEK_CUR、SEEK_END

(4)     ssize_t read(int fd, void *buf, size_t nbytes);

                                          若成功则返回读到的字节数，若已到文件结尾则返回0，若出错则返回-1

       ssize_t 带符号，size_t 不带符号

(5)     ssize_t write(int fd, const void *buf, size_t nbytes);

                                                 若成功则返回已写的字节数，若出错则返回-1

(6)     int dup(int fd);

int dup2(int fds, int fds2);

                                                 若成功则返回新的文件描述符，若出错则返回-1

(7)     int fsync(int fd);

int fdatasync(int fd);

void sync(void);

                                                 若成功则返回0，若出错则返回-1

(8)     int fcntl(int fd, int cmd, …/*int arg*/);     改变打开文件的属性

                                                 若成功则依赖于cmd，若出错则返回-1

       cmd:       F_DUPFD、F_SETFD、F_GETFD、

                     F_GETFL、F_SETFL、

                     F_GETOWN、F_SETOWN

(9)     #include

#include

int ioctl(int fd, int request, …);

                                                 若成功则返回其他值，若出错则返回-1