return frequency and sample rate as unsigned integers

include/rtl-sdr.h

@@ -41,7 +41,13 @@ RTLSDR_API int rtlsdr_close(rtlsdr_dev_t *dev);
 
 RTLSDR_API int rtlsdr_set_center_freq(rtlsdr_dev_t *dev, uint32_t freq);
 
-RTLSDR_API int rtlsdr_get_center_freq(rtlsdr_dev_t *dev);
+/*!
+ * Get actual frequency the device is tuned to.
+ *
+ * \param dev the device handle given by rtlsdr_open()
+ * \return 0 on error, frequency in Hz otherwise
+ */
+RTLSDR_API uint32_t rtlsdr_get_center_freq(rtlsdr_dev_t *dev);
 
 RTLSDR_API int rtlsdr_set_freq_correction(rtlsdr_dev_t *dev, int ppm);
 
@@ -54,7 +60,13 @@ RTLSDR_API int rtlsdr_get_tuner_gain(rtlsdr_dev_t *dev);
 /* this will select the baseband filters according to the requested sample rate */
 RTLSDR_API int rtlsdr_set_sample_rate(rtlsdr_dev_t *dev, uint32_t rate);
 
-RTLSDR_API int rtlsdr_get_sample_rate(rtlsdr_dev_t *dev);
+/*!
+ * Get actual sample rate the device is configured to.
+ *
+ * \param dev the device handle given by rtlsdr_open()
+ * \return 0 on error, sample rate in Hz otherwise
+ */
+RTLSDR_API uint32_t rtlsdr_get_sample_rate(rtlsdr_dev_t *dev);
 
 /* streaming functions */
 

src/rtl-sdr.c

@@ -459,10 +459,10 @@ int rtlsdr_set_center_freq(rtlsdr_dev_t *dev, uint32_t freq)
 	return r;
 }
 
-int rtlsdr_get_center_freq(rtlsdr_dev_t *dev)
+uint32_t rtlsdr_get_center_freq(rtlsdr_dev_t *dev)
 {
 	if (!dev || !dev->tuner)
-		return -1;
+		return 0;
 
 	return dev->tuner->freq;
 }
@@ -554,10 +554,10 @@ int rtlsdr_set_sample_rate(rtlsdr_dev_t *dev, uint32_t samp_rate)
 	return 0;
 }
 
-int rtlsdr_get_sample_rate(rtlsdr_dev_t *dev)
+uint32_t rtlsdr_get_sample_rate(rtlsdr_dev_t *dev)
 {
 	if (!dev)
-		return -1;
+		return 0;
 
 	return dev->rate;
 }