feat: postgreact: hello world

package/c/postgreact/postgreact.c

@@ -0,0 +1,16 @@
+#include "postgres.h"
+#include "fmgr.h"
+#include "utils/builtins.h" /* for text_to_cstring and cstring_to_text */
+
+#ifdef PG_MODULE_MAGIC
+PG_MODULE_MAGIC;
+#endif
+
+/* Define the function hello */
+PG_FUNCTION_INFO_V1(hello);
+
+/* Implement the function */
+Datum hello(PG_FUNCTION_ARGS) 
+{
+    PG_RETURN_TEXT_P(cstring_to_text("Hello, world!"));
+}