A file descriptor as returned from fd_open.
A buffer or string to be read from the file.
An integer specifying the length of the buffer or string.
An integer specifying the position in the file to begin reading the buffer or string.
This function reads a buffer or string from the specified file.
When an error occurs, the following errnos are possible:
EAGAIN The O_NONBLOCK flag is set for the fd and the process would be delayed in the read operation.
EBADF The passed fd is invalid or not open for writing.
EFBIG File is too big.
EINTR Read was interrupted by a signal.
EINVAL iovcnt was less than or equal to 0, or greater than UIO_MAXIOV.
EIO Physical IO error.
Gamma> x = fd_open("/fd/ser1",O_RDWR);
4
Gamma> fd_read(x,"hello\n");
6
Gamma> fd_close(x);
t