sopenfd()

Open for shared access a file associated with a given descriptor

Synopsis:

#include <unistd.h>

int sopenfd( int fd,
             int oflag,
             int sflag );

Library:

libc

Description:

The sopenfd() function opens for shared access the file associated with the file descriptor, fd. The access mode, oflag, must be equal to or more restrictive than the access mode of the source fd.

The oflag argument specifies how the file is to be opened, and is a combination of the following bits:

O_RDONLY

Permit the file to be only read.

O_WRONLY

Permit the file to be only written.

O_RDWR

Permit the file to be both read and written.

O_APPEND

Cause each record that is written to be written at the end of the file.

O_TRUNC

Causes the file to be truncated to contain no data when the file exists; has no effect when the file doesn't exist.

The sflag argument specifies how the file is to be shared, and is a combination of the following bits:

SH_COMPAT

Set compatibility mode.

SH_DENYRW

Prevent read or write access to the file.

SH_DENYWR

Prevent write access of the file.

SH_DENYRD

Prevent read access to the file.

SH_DENYNO

Permit both read and write access to the file.

Note that:

openfd( fd, oflag );

is the same as:

sopenfd( fd, oflag, SH_DENYNO );

Returns:

The file descriptor, or -1 if an error occurs (errno is set).

Errors:

EBADF

Invalid file descriptor fd.

EACCES

The access mode specified by oflag isn't equal to or more restrictive than the access mode of the source fd.

EBUSY

Sharing mode (sflag) was denied due to a conflicting open.

Classification:

Unix

See also:

openfd()