X-Git-Url: http://sigrok.org/gitweb/?a=blobdiff_plain;f=libserialport.h.in;h=41948c1828eee3bab22fdc1e60187233489e88c8;hb=2c827b218813f2663fc3fb09d2ad61f50c4ec1ff;hp=649eb2c8755bf9814deaa66f873b61fe4ff468da;hpb=e432ce60065f9d073dca5d639a4fc179de566639;p=libserialport.git

diff --git a/libserialport.h.in b/libserialport.h.in
index 649eb2c..41948c1 100644
--- a/libserialport.h.in
+++ b/libserialport.h.in
@@ -120,8 +120,6 @@ enum sp_mode {
 	SP_MODE_READ = 1,
 	/** Open port for write access. */
 	SP_MODE_WRITE = 2,
-	/** Open port in non-blocking mode. */
-	SP_MODE_NONBLOCK = 4,
 };
 
 /** Buffer selection. */
@@ -758,34 +756,114 @@ enum sp_return sp_set_flowcontrol(struct sp_port *port, enum sp_flowcontrol flow
 */
 
 /**
- * Read bytes from the specified serial port.
+ * Read bytes from the specified serial port, blocking until complete.
  *
- * Note that this function may return after reading less than the specified
- * number of bytes; it is the user's responsibility to iterate as necessary
- * in this case.
+ * @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.
+ * @param count Requested number of bytes to read.
+ * @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
+ *         timeout was reached before the requested number of bytes was
+ *         available. If timeout is zero, the function will always return
+ *         either the requested number of bytes or a negative error code.
+ */
+enum sp_return sp_blocking_read(struct sp_port *port, void *buf, size_t count, unsigned int timeout);
+
+/**
+ * Read bytes from the specified serial port, without blocking.
  *
  * @param port Pointer to port structure.
  * @param buf Buffer in which to store the bytes read.
  * @param count Maximum number of bytes to read.
  *
- * @return The number of bytes read on success, or a negative error code.
+ * @return The number of bytes read on success, or a negative error code. The
+ *         number of bytes returned may be any number from zero to the maximum
+ *         that was requested.
+ */
+enum sp_return sp_nonblocking_read(struct sp_port *port, void *buf, size_t count);
+
+/**
+ * Write bytes to the specified serial port, blocking until complete.
+ *
+ * Note that this function only ensures that the accepted bytes have been
+ * written to the OS; they may be held in driver or hardware buffers and not
+ * yet physically transmitted. To check whether all written bytes have actually
+ * 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 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
+ *         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.
  */
-enum sp_return sp_read(struct sp_port *port, void *buf, size_t count);
+enum sp_return sp_blocking_write(struct sp_port *port, const void *buf, size_t count, unsigned int timeout);
 
 /**
- * Write bytes to the specified serial port.
+ * Write bytes to the specified serial port, without blocking.
  *
- * Note that this function may return after writing less than the specified
- * number of bytes; it is the user's responsibility to iterate as necessary
- * in this case.
+ * Note that this function only ensures that the accepted bytes have been
+ * written to the OS; they may be held in driver or hardware buffers and not
+ * yet physically transmitted. To check whether all written bytes have actually
+ * been transmitted, use the sp_output_waiting() function. To wait until all
+ * written bytes have actually been transmitted, use the sp_drain() function.
  *
  * @param port Pointer to port structure.
  * @param buf Buffer containing the bytes to write.
  * @param count Maximum number of bytes to write.
  *
  * @return The number of bytes written on success, or a negative error code.
+ *         The number of bytes returned may be any number from zero to the
+ *         maximum that was requested.
+ */
+enum sp_return sp_nonblocking_write(struct sp_port *port, const void *buf, size_t count);
+
+/**
+ * Gets the number of bytes waiting in the input buffer.
+ *
+ * @param port Pointer to port structure.
+ *
+ * @return Number of bytes waiting on success, a negative error code otherwise.
  */
-enum sp_return sp_write(struct sp_port *port, const void *buf, size_t count);
+enum sp_return sp_input_waiting(struct sp_port *port);
+
+/**
+ * Gets the number of bytes waiting in the output buffer.
+ *
+ * @param port Pointer to port structure.
+ *
+ * @return Number of bytes waiting on success, a negative error code otherwise.
+ */
+enum sp_return sp_output_waiting(struct sp_port *port);
 
 /**
  * Flush serial port buffers. Data in the selected buffer(s) is discarded.
@@ -800,6 +878,13 @@ enum sp_return sp_flush(struct sp_port *port, enum sp_buffer buffers);
 /**
  * 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.