Make sp_flush take an option for what to flush.

diff --git a/libserialport.h.in b/libserialport.h.in
index fa5ba1a829c95a96be03a84c1ab370972d97b2f0..12e9cba3a5556ae468f1957d4f36e2aff0304b31 100644 (file)
--- a/libserialport.h.in
+++ b/libserialport.h.in
@@ -109,6 +109,16 @@ enum sp_mode {
        SP_MODE_NONBLOCK = 4,
 };
 
+/** Buffer selection. */
+enum sp_buffer {
+       /** Input buffer. */
+       SP_BUF_INPUT = 1,
+       /** Output buffer. */
+       SP_BUF_OUTPUT = 2,
+       /** Both buffers. */
+       SP_BUF_BOTH = 3,
+};
+
 /** Parity settings. */
 enum sp_parity {
        /** Special value to indicate setting should be left alone. */
@@ -506,12 +516,14 @@ enum sp_return sp_read(struct sp_port *port, void *buf, size_t count);
 enum sp_return sp_write(struct sp_port *port, const void *buf, size_t count);
 
 /**
- * Flush serial port buffers.
+ * Flush serial port buffers. Data in the selected buffer(s) is discarded.
+ *
+ * @param buffers Which buffer(s) to flush.
  *
  * @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG
  *         if an invalid port is passed.
  */
-enum sp_return sp_flush(struct sp_port *port);
+enum sp_return sp_flush(struct sp_port *port, enum sp_buffer buffers);
 
 /**
  * @}

diff --git a/serialport.c b/serialport.c
index 353cd347118c61c468584fd4256d51b0001a6933..92156b476471cdf73f3a3efefe05bba69aff6795 100644 (file)
--- a/serialport.c
+++ b/serialport.c
@@ -505,17 +505,31 @@ enum sp_return sp_close(struct sp_port *port)
        return SP_OK;
 }
 
-enum sp_return sp_flush(struct sp_port *port)
+enum sp_return sp_flush(struct sp_port *port, enum sp_buffer buffers)
 {
        CHECK_PORT();
 
 #ifdef _WIN32
+       DWORD flags = 0;
+       if (buffers & SP_BUF_INPUT)
+               flags |= PURGE_RXCLEAR;
+       if (buffers & SP_BUF_OUTPUT)
+               flags |= PURGE_TXCLEAR;
+
        /* Returns non-zero upon success, 0 upon failure. */
-       if (PurgeComm(port->hdl, PURGE_RXCLEAR | PURGE_TXCLEAR) == 0)
+       if (PurgeComm(port->hdl, flags) == 0)
                return SP_ERR_FAIL;
 #else
+       int flags = 0;
+       if (buffers & SP_BUF_BOTH)
+               flags = TCIOFLUSH;
+       else if (buffers & SP_BUF_INPUT)
+               flags = TCIFLUSH;
+       if (buffers & SP_BUF_OUTPUT)
+               flags = TCOFLUSH;
+
        /* Returns 0 upon success, -1 upon failure. */
-       if (tcflush(port->fd, TCIOFLUSH) < 0)
+       if (tcflush(port->fd, flags) < 0)
                return SP_ERR_FAIL;
 #endif
        return SP_OK;