Basic Syscall API
[Level 0 API (Syscall API)]

Collaboration diagram for Basic Syscall API:

Functions
int	a4l_sys_open (const char *fname)
	Open an Analogy device.
int	a4l_sys_close (int fd)
	Close an Analogy device.
int	a4l_sys_read (int fd, void *buf, size_t nbyte)
	Read from an Analogy device.
int	a4l_sys_write (int fd, void *buf, size_t nbyte)
	Write to an Analogy device.

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Function Documentation

int a4l_sys_close

(

int

fd

)

Close an Analogy device.

Parameters:

[in]

fd

File descriptor as returned by a4l_sys_open()

Returns:

0 on success, otherwise a negative error code.

Referenced by a4l_close(), and a4l_open().

int a4l_sys_open

(

const char *

fname

)

Open an Analogy device.

Parameters:

[in]

fname

Device name

Returns:

Positive file descriptor value on success, otherwise a negative error code.

Referenced by a4l_open().

int a4l_sys_read	(	int	fd,
		void *	buf,
		size_t	nbyte
	)

Read from an Analogy device.

The function a4l_read() is only useful for acquisition configured through an Analogy command.

Parameters:

[in]	fd	File descriptor as returned by a4l_sys_open()
[out]	buf	Input buffer
[in]	nbyte	Number of bytes to read

Returns:

Number of bytes read. Otherwise:

• -EINVAL is returned if some argument is missing or wrong (Please, type "dmesg" for more info)
• -ENOENT is returned if the device's reading subdevice is idle (no command was sent)
• -EFAULT is returned if a user <-> kernel transfer went wrong
• -EINTR is returned if calling task has been unblocked by a signal

Referenced by a4l_async_read().

int a4l_sys_write	(	int	fd,
		void *	buf,
		size_t	nbyte
	)

Write to an Analogy device.

The function a4l_write() is only useful for acquisition configured through an Analogy command.

Parameters:

[in]	fd	File descriptor as returned by a4l_sys_open()
[in]	buf	Output buffer
[in]	nbyte	Number of bytes to write

Returns:

Number of bytes written. Otherwise:

• -EINVAL is returned if some argument is missing or wrong (Please, type "dmesg" for more info)
• -ENOENT is returned if the device's writing subdevice is idle (no command was sent)
• -EFAULT is returned if a user <-> kernel transfer went wrong
• -EINTR is returned if calling task has been unblocked by a signal

Referenced by a4l_async_write().