Tlpi Ch 4

Front 1

File Descriptor

Back 1

A usually small nonnegative integer used to refer to all types of open files.

Front 2

What are the three standard file descriptors?

Back 2

0 - standard input (stdin)
1 - standard output (stdout)
2 - standard error (stderr)

Front 3

open(pathname, flags, mode)

Back 3

Opens the file identified by pathname, returning a file descriptor used to refer to the open file in subsequent calls.

Front 4

Flags

Back 4

An argument that specifies whether the file is to be opened for reading, writing, or both.

Front 5

Mode

Back 5

An argument that specifies the permissions to be placed on the file if it is created by this call.

Front 6

read(rd, buffer, count)

Back 6

Reads at most count bytes from the open file referred to by fd and stores them in buffer.

Front 7

write(fd, buffer, count)

Back 7

Writes up to count bytes from buffer to the open file referred to by fd.

Front 8

close(fd)

Back 8

Called after all I/O has been completed, in order to release the file descriptor fd and its associated kernel resources.

Front 9

File Access Mode Flags

Back 9

These are the O_RDONLY, O_WRONLY, and O_RDWR flags. They can be retrieved using the fcntl() operation.

Front 10

File Creation Flags

Back 10

These flags control various aspects of the behavior of the open() call, as well as options for subsequent I/O operations. These flags can't be retrieved or changed.

Front 11

Open File Status Flags

Back 11

These are the remaining flags. They can be retrieved and modified using the fcntl() operations.

Front 12

creat()

Back 12

System call creates and opens a new file with the given pathname, or if the file already exists, opens the file and truncates it to zero length.