6.2. CA Function Calls

6.2.1. open()

DESCRIPTION

This system call opens a named ca device (e.g. /dev/ost/ca) for subsequent use.

When an open() call has succeeded, the device will be ready for use. The significance of blocking or non-blocking mode is described in the documentation for functions where there is a difference. It does not affect the semantics of the open() call itself. A device opened in blocking mode can later be put into non-blocking mode (and vice versa) using the F_SETFL command of the fcntl system call. This is a standard system call, documented in the Linux manual page for fcntl. Only one user can open the CA Device in O_RDWR mode. All other attempts to open the device in this mode will fail, and an error code will be returned.

SYNOPSIS

int open(const char ⋆deviceName, int flags);

PARAMETERS

const char *deviceName

Name of specific video device.

int flags

A bit-wise OR of the following flags:

O_RDONLY read-only access

O_RDWR read/write access

O_NONBLOCK open in non-blocking mode

(blocking mode is the default)

ERRORS

ENODEV

Device driver not loaded/available.

EINTERNAL

Internal error.

EBUSY

Device or resource busy.

EINVAL

Invalid argument.

6.2.2. close()

DESCRIPTION

This system call closes a previously opened audio device.

SYNOPSIS

int close(int fd);

PARAMETERS

int fd

File descriptor returned by a previous call to open().

ERRORS

EBADF

fd is not a valid open file descriptor.