fix up casting functions

examples/plugins/minio/plugin.go

@@ -0,0 +1,73 @@
+// This example demonstrates a src element that reads from objects in a minio bucket.
+// Since minio implements the S3 API this plugin could also be used for S3 buckets by
+// setting the correct endpoints and credentials.
+//
+// By default this plugin will use the credentials set in the environment at MINIO_ACCESS_KEY_ID
+// and MINIO_SECRET_ACCESS_KEY however these can also be set on the element directly.
+//
+//
+// In order to build the plugin for use by GStreamer, you can do the following:
+//
+//     $ go build -o libgstminio.so -buildmode c-shared .
+//
+package main
+
+import "C"
+
+import (
+	"unsafe"
+
+	"github.com/tinyzimmer/go-gst/gst"
+	"github.com/tinyzimmer/go-gst/gst/base"
+)
+
+// The metadata for this plugin
+var pluginMeta = &gst.PluginMetadata{
+	MajorVersion: gst.VersionMajor,
+	MinorVersion: gst.VersionMinor,
+	Name:         "minio-plugins",
+	Description:  "GStreamer plugins for reading and writing from Minio",
+	Version:      "v0.0.1",
+	License:      gst.LicenseLGPL,
+	Source:       "gst-pipeline-operator",
+	Package:      "plugins",
+	Origin:       "https://github.com/tinyzimmer/gst-pipeline-operator",
+	ReleaseDate:  "2021-01-12",
+	// The init function is called to register elements provided by the plugin.
+	Init: func(plugin *gst.Plugin) bool {
+		if ok := gst.RegisterElement(
+			plugin,
+			// The name of the element
+			"miniosrc",
+			// The rank of the element
+			gst.RankNone,
+			// The GoElement implementation for the element
+			&minioSrc{},
+			// The base subclass this element extends
+			base.ExtendsBaseSrc,
+		); !ok {
+			return ok
+		}
+
+		if ok := gst.RegisterElement(
+			plugin,
+			// The name of the element
+			"miniosink",
+			// The rank of the element
+			gst.RankNone,
+			// The GoElement implementation for the element
+			&minioSink{},
+			// The base subclass this element extends
+			base.ExtendsBaseSink,
+		); !ok {
+			return ok
+		}
+
+		return true
+	},
+}
+
+func main() {}
+
+//export gst_plugin_minio_get_desc
+func gst_plugin_minio_get_desc() unsafe.Pointer { return pluginMeta.Export() }