Implement RETRO_ENVIRONMENT_GET_TARGET_SAMPLE_RATE - optional to implement.

Lets the core query the frontend for the desired target output samplerate.
Will return false if the output samplerate cannot be queried,  will return
true if it's implemented. data returned will be of unsigned type

Author: LibretroAdmin

libretro-common/include/libretro.h

@@ -2575,6 +2575,18 @@ enum retro_mod
  */
 #define RETRO_ENVIRONMENT_GET_FILE_BROWSER_START_DIRECTORY 80
 
+/**
+ * Returns the audio sample rate the frontend is targeting, in Hz.
+ * The intended use case is for the core to use the result to select an ideal sample rate.
+ *
+ * @param[out] data <tt>float *</tt>.
+ * Pointer to the \c float in which the frontend will store its target sample rate.
+ * Behavior is undefined if \c data is <tt>NULL</tt>.
+ * @return \c true if this environment call is available,
+ * regardless of the value returned in \c data.
+*/
+#define RETRO_ENVIRONMENT_GET_TARGET_SAMPLE_RATE (81 | RETRO_ENVIRONMENT_EXPERIMENTAL)
+
 /**@}*/
 
 /**

runloop.c

@@ -3333,6 +3333,15 @@ bool runloop_environment_cb(unsigned cmd, void *data)
          *(unsigned *)data = 2;
          break;
 
+      case RETRO_ENVIRONMENT_GET_TARGET_SAMPLE_RATE:
+      {
+         if (!settings)
+            return false;
+
+         *(unsigned *)data = settings->uints.audio_output_sample_rate;
+         break;
+      }
+
       case RETRO_ENVIRONMENT_GET_TARGET_REFRESH_RATE:
       {
          /* Try to use the polled refresh rate first.  */