openfd()

Arguments:

fd

A file descriptor associated with the file that you want to open.

oflag

How you want to open the file; 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's written to be written at the end of the file.
• O_CLOEXEC — close the file descriptor if the program calls one of the exec*(), posix_spawn*(), or spawn*() functions.
• O_LARGEFILE — allow the file offset to be 64 bits long.
• O_TRUNC — truncate the file to contain no data.

Library:

libc

Use the -l c option to qcc to link against this library. This library is usually included automatically.

Description:

The openfd() function opens the file associated with the file descriptor, fd. This is similar to dup(), except the new fd has private access modes and offset. The access mode specified in oflag must be equal to or more restrictive than the access mode of the source fd.

Returns:

A file descriptor, or -1 if an error occurred (errno is set).

Errors:

EBADF

Invalid file descriptor fd.

EACCES

The access mode specified in 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 (see sopenfd()).

Examples:

#include <unistd.h>
#include <stdlib.h>
#include <fcntl.h>

int main ( void )
{
    int fd, fd2, oflag;

    fd = open ("/etc/passwd", O_RDONLY);
    fd2 = openfd ( fd, O_RDONLY );
    return EXIT_SUCCESS;
}

Classification:

QNX OS