diff --git a/src/interfaces/api/c/dtfft_api_c.c b/src/interfaces/api/c/dtfft_api_c.c
index bf22782..424697e 100644
--- a/src/interfaces/api/c/dtfft_api_c.c
+++ b/src/interfaces/api/c/dtfft_api_c.c
@@ -152,7 +152,7 @@ dtfft_get_error_string(const dtfft_error_code_t error_code)
 
 dtfft_error_code_t
 dtfft_get_pencil(dtfft_plan_t plan, int8_t dim, dtfft_pencil_t *pencil) {
-  return dtfft_get_pencil_c(get_plan_handle(plan), &dim, (void*)pencil);
+  return (dtfft_error_code_t)dtfft_get_pencil_c(get_plan_handle(plan), &dim, (void*)pencil);
 }
 
 #ifdef DTFFT_WITH_CUDA
diff --git a/src/interfaces/api/include/dtfft_api.h b/src/interfaces/api/include/dtfft_api.h
index 1d06aeb..76885bf 100644
--- a/src/interfaces/api/include/dtfft_api.h
+++ b/src/interfaces/api/include/dtfft_api.h
@@ -67,7 +67,7 @@ dtfft_get_error_string_c(const int32_t*, char*, size_t*);
 
 extern
 int32_t
-dtfft_get_pencil_c(const void*, int8_t*, void **);
+dtfft_get_pencil_c(const void*, int8_t*, void *);
 
 #ifdef DTFFT_WITH_CUDA