Add header to runtime environment

Author: awvwgk

include/gauxc/runtime_environment.h

@@ -16,6 +16,7 @@
 #else
 #include <stddef.h>
 #endif
+#include <gauxc/types.h>
 #include <gauxc/status.h>
 #include <gauxc/util/mpi.h>
 
@@ -28,6 +29,7 @@ namespace GauXC::C {
  * @brief GauXC C API RuntimeEnvironment handle.
  */
 typedef struct GauXCRuntimeEnvironment {
+  GauXCHeader hdr; ///< Header for internal use.
   void* ptr; ///< Pointer to the RuntimeEnvironment instance.
 #ifdef GAUXC_HAS_DEVICE
   void* device_ptr; ///< Pointer to the DeviceRuntimeEnvironment instance (if applicable).

src/c_runtime_environment.cxx

@@ -28,6 +28,7 @@ GauXCRuntimeEnvironment gauxc_runtime_environment_new(
 
   try {
     env.ptr = new RuntimeEnvironment(GAUXC_MPI_CODE(comm));
+    env.hdr = GauXCHeader{GauXC_Type_RuntimeEnvironment};
     status->code = 0;
   } catch (...) {
     status->code = 1;
@@ -65,6 +66,7 @@ GauXCRuntimeEnvironment gauxc_device_runtime_environment_new(
   double fill_fraction
 ) {
   GauXCRuntimeEnvironment env{};
+  env.hdr = GauXCHeader{GauXC_Type_RuntimeEnvironment};
   env.ptr = nullptr;
   env.device_ptr = nullptr;
 
@@ -86,6 +88,7 @@ GauXCRuntimeEnvironment gauxc_device_runtime_environment_new_mem(
   size_t mem_sz
 ) {
   GauXCRuntimeEnvironment env{};
+  env.hdr = GauXCHeader{GauXC_Type_RuntimeEnvironment};
   env.ptr = nullptr;
   env.device_ptr = nullptr;