struct serial
{
int fd; /* File descriptor */
+ /* File descriptor for a separate error stream that should be
+ immediately forwarded to gdb_stderr. This may be -1.
+ If != -1, this descriptor should be non-blocking or
+ ops->avail should be non-NULL. */
+ int error_fd;
struct serial_ops *ops; /* Function vector */
void *state; /* Local context info for open FD */
serial_ttystate ttystate; /* Not used (yet) */
/* Perform a low-level write operation, writing (at most) COUNT
bytes from BUF. */
int (*write_prim)(struct serial *scb, const void *buf, size_t count);
+ /* Return that number of bytes that can be read from FD
+ without blocking. Return value of -1 means that the
+ the read will not block even if less that requested bytes
+ are available. */
+ int (*avail)(struct serial *scb, int fd);
#ifdef USE_WIN32API
/* Return a handle to wait on, indicating available data from SCB