[C-API] add ov_get_last_error_msg() API (openvinotoolkit#20643)

src/bindings/c/include/openvino/c/ov_common.h

@@ -204,3 +204,10 @@ ov_get_error_info(ov_status_e status);
  */
 OPENVINO_C_API(void)
 ov_free(const char* content);
+
+/**
+ * @brief Get the last error msg.
+ * @ingroup ov_base_c_api
+ */
+OPENVINO_C_API(const char*)
+ov_get_last_err_msg();

src/bindings/c/src/common.h

@@ -14,13 +14,15 @@
 #include "openvino/core/except.hpp"
 #include "openvino/openvino.hpp"
 
-#define CATCH_IE_EXCEPTION(StatusCode, ExceptionType) \
-    catch (const InferenceEngine::ExceptionType&) {   \
-        return ov_status_e::StatusCode;               \
+#define CATCH_IE_EXCEPTION(StatusCode, ExceptionType)  \
+    catch (const InferenceEngine::ExceptionType& ex) { \
+        dup_last_err_msg(ex.what());                   \
+        return ov_status_e::StatusCode;                \
     }
 
 #define CATCH_OV_EXCEPTION(StatusCode, ExceptionType) \
-    catch (const ov::ExceptionType&) {                \
+    catch (const ov::ExceptionType& ex) {             \
+        dup_last_err_msg(ex.what());                  \
         return ov_status_e::StatusCode;               \
     }
 
@@ -41,6 +43,7 @@
     CATCH_IE_EXCEPTION(NETWORK_NOT_READ, NetworkNotRead)      \
     CATCH_IE_EXCEPTION(INFER_CANCELLED, InferCancelled)       \
     catch (...) {                                             \
+        dup_last_err_msg("An unknown exception occurred");    \
         return ov_status_e::UNKNOW_EXCEPTION;                 \
     }
 
@@ -224,3 +227,4 @@ struct mem_istream : virtual mem_stringbuf, std::istream {
 
 char* str_to_char_array(const std::string& str);
 ov::element::Type get_element_type(ov_element_type_e type);
+void dup_last_err_msg(const char* msg);

src/bindings/c/src/ov_core.cpp

@@ -17,6 +17,22 @@ char* str_to_char_array(const std::string& str) {
     return char_array;
 }
 
+static std::string last_err_msg;
+static std::mutex last_msg_mutex;
+void dup_last_err_msg(const char* msg) {
+    std::lock_guard<std::mutex> lock(last_msg_mutex);
+    last_err_msg = std::string(msg);
+}
+
+const char* ov_get_last_err_msg() {
+    std::lock_guard<std::mutex> lock(last_msg_mutex);
+    char* res = nullptr;
+    if (!last_err_msg.empty()) {
+        res = str_to_char_array(last_err_msg);
+    }
+    return res;
+}
+
 ov_status_e ov_get_openvino_version(ov_version_t* version) {
     if (!version) {
         return ov_status_e::INVALID_C_PARAM;
@@ -66,6 +82,10 @@ ov_status_e ov_core_create(ov_core_t** core) {
 void ov_core_free(ov_core_t* core) {
     if (core)
         delete core;
+
+    // release err msg buffer, there will be no err msg after core is freed.
+    std::lock_guard<std::mutex> lock(last_msg_mutex);
+    last_err_msg.clear();
 }
 
 ov_status_e ov_core_read_model(const ov_core_t* core,

src/bindings/c/tests/ov_core_test.cpp

@@ -33,6 +33,7 @@ class ov_core_test : public ov_capi_test_base {
         ov_capi_test_base::TearDown();
     }
 };
+
 INSTANTIATE_TEST_SUITE_P(ov_core, ov_core_test, ::testing::Values("CPU"));
 
 TEST_P(ov_core_test, ov_core_create_with_config) {
@@ -699,4 +700,37 @@ TEST_P(ov_core_test, ov_core_compile_model_from_file_unicode) {
 }
 #endif
 
+using ov_util_test = ov_core_test;
+INSTANTIATE_TEST_SUITE_P(ov_capi_test, ov_util_test, ::testing::Values("CPU"));
+
+TEST_P(ov_util_test, ov_get_last_err_msg_check) {
+    auto device_name = GetParam();
+    ov_core_t* core = nullptr;
+    OV_EXPECT_OK(ov_core_create(&core));
+    EXPECT_NE(nullptr, core);
+
+    const char* key = ov_property_key_inference_num_threads;
+    OV_EXPECT_OK(ov_core_set_property(core, device_name.c_str(), key, "abc"));
+
+    char* ret = nullptr;
+    OV_EXPECT_NOT_OK(ov_core_get_property(core, device_name.c_str(), key, &ret));
+
+    auto err_msg = ov_get_last_err_msg();
+    EXPECT_NE(nullptr, err_msg);
+    ov_free(err_msg);
+    ov_free(ret);
+    ov_core_free(core);
+}
+
+TEST_P(ov_util_test, ov_get_last_err_msg_check_empty_msg) {
+    auto device_name = GetParam();
+    ov_core_t* core = nullptr;
+    OV_EXPECT_OK(ov_core_create(&core));
+    EXPECT_NE(nullptr, core);
+
+    auto err_msg = ov_get_last_err_msg();
+    EXPECT_EQ(nullptr, err_msg);
+    ov_core_free(core);
+}
+
 }  // namespace