Add export annotations for functions in c10 (#18464)

Summary:
Fixes #18461.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/18464

Differential Revision: D14620963

Pulled By: ezyang

fbshipit-source-id: c11f3967de2ac69c7140767c8fe73a85555e9f40

diff --git a/c10/core/TensorTypeId.h b/c10/core/TensorTypeId.h
index 3a8648a..8754863 100644 (file)
--- a/c10/core/TensorTypeId.h
+++ b/c10/core/TensorTypeId.h
@@ -35,7 +35,7 @@ class C10_API TensorTypeId final
   friend C10_API std::string toString(TensorTypeId);
 };
 
-std::string toString(TensorTypeId id);
+C10_API std::string toString(TensorTypeId id);
 
 C10_API std::ostream& operator<<(std::ostream&, c10::TensorTypeId);