*/
/**
- * Read bytes from the specified serial port, blocking until available.
+ * Read bytes from the specified serial port, blocking until complete.
+ *
+ * @warning If your program runs on Unix, defines its own signal handlers, and
+ * needs to abort blocking reads when these are called, then you
+ * should not use this function. It repeats system calls that return
+ * with EINTR. To be able to abort a read from a signal handler, you
+ * should implement your own blocking read using sp_nonblocking_read()
+ * together with a blocking method that makes sense for your program.
+ * E.g. you can obtain the file descriptor for an open port using
+ * sp_get_port_handle() and use this to call select() or pselect(),
+ * with appropriate arrangements to return if a signal is received.
*
* @param port Pointer to port structure.
* @param buf Buffer in which to store the bytes read.
* been transmitted, use the sp_output_waiting() function. To wait until all
* written bytes have actually been transmitted, use the sp_drain() function.
*
+ * @warning If your program runs on Unix, defines its own signal handlers, and
+ * needs to abort blocking writes when these are called, then you
+ * should not use this function. It repeats system calls that return
+ * with EINTR. To be able to abort a write from a signal handler, you
+ * should implement your own blocking write using sp_nonblocking_write()
+ * together with a blocking method that makes sense for your program.
+ * E.g. you can obtain the file descriptor for an open port using
+ * sp_get_port_handle() and use this to call select() or pselect(),
+ * with appropriate arrangements to return if a signal is received.
+ *
* @param port Pointer to port structure.
* @param buf Buffer containing the bytes to write.
* @param count Requested number of bytes to write.
* @param timeout Timeout in milliseconds, or zero to wait indefinitely.
*
- * @return The number of bytes read on success, or a negative error code. If
- * the number of bytes returned is less than that requested, the
+ * @return The number of bytes written on success, or a negative error code.
+ * If the number of bytes returned is less than that requested, the
* timeout was reached before the requested number of bytes was
- * sent. If timeout is zero, the function will always return
+ * written. If timeout is zero, the function will always return
* either the requested number of bytes or a negative error code. In
* the event of an error there is no way to determine how many bytes
* were sent before the error occured.
/**
* Wait for buffered data to be transmitted.
*
+ * @warning If your program runs on Unix, defines its own signal handlers, and
+ * needs to abort draining the output buffer when when these are
+ * called, then you should not use this function. It repeats system
+ * calls that return with EINTR. To be able to abort a drain from a
+ * signal handler, you would need to implement your own blocking
+ * drain by polling the result of sp_output_waiting().
+ *
* @param port Pointer to port structure.
*
* @return SP_OK upon success, a negative error code otherwise.