Write to the Unity logs from your native plug-inA set of code created outside of Unity that creates functionality in Unity. There are two kinds of plug-ins you can use in Unity: Managed plug-ins (managed .NET assemblies created with tools like Visual Studio) and Native plug-ins (platform-specific native code libraries). More info
See in Glossary code using the IUnityLog interface. Low-level native APIs for logging are provided in the IUnityLog.h header file, located in the PluginAPI folder.
The file contains a single Log function with the following decalaration:
void(UNITY_INTERFACE_API * Log)(UnityLogType type, const char* message, const char *fileName, const int fileLine);
You can call this function directly as follows:
s_UnityLog->Log(kUnityLogTypeLog, "Here is a regular log", __FILE__, __LINE__);
However, for convenience the native logging API defines the following macros that wrap different log-level calls to the Log function:
| Macro | Description |
|---|---|
UNITY_LOG(PTR_, MSG_) |
Uses the log interface passed as a pointer (PTR_) to write the provided char* MSG_ as a regular log message. Equivalent to the managed API Debug.Log. |
UNITY_LOG_WARNING(PTR_, MSG_) |
Uses the log interface passed as a pointer (PTR_) to write the provided char* MSG_ as a warning-level log message. Equivalent to the managed API Debug.LogWarning. |
UNITY_LOG_ERROR(PTR_, MSG_) |
Uses the log interface passed as a pointer (PTR_) to write the provided char* MSG_ as an error-level log message. Equivalent to the managed API Debug.LogError. |
The following code example implements the IUnityLog interface in C++ and uses these predefined macros to write different levels of log output:
#include "IUnityLog.h"
static IUnityLog* s_UnityLog = NULL;
// Additional macros to include file and line number from the native code
#define UNITY_LOG_STRINGIZE_DETAIL(x) #x
#define UNITY_LOG_STRINGIZE(x) UNITY_LOG_STRINGIZE_DETAIL(x)
#define COMPOSE(MESSAGE) "[" __FILE__ ":" UNITY_LOG_STRINGIZE(__LINE__) "] " MESSAGE
#define NATIVE_LOG(PTR, MESSAGE) UNITY_LOG(PTR, COMPOSE(MESSAGE))
#define NATIVE_WARNING(PTR, MESSAGE) UNITY_LOG_WARNING(PTR, COMPOSE(MESSAGE))
#define NATIVE_ERROR(PTR, MESSAGE) UNITY_LOG_ERROR(PTR, COMPOSE(MESSAGE))
// Unity plugin load event
extern "C" void UNITY_INTERFACE_EXPORT UNITY_INTERFACE_API UnityPluginLoad(IUnityInterfaces * unityInterfacesPtr)
{
s_UnityLog = unityInterfacesPtr->Get<IUnityLog>();
}
// Unity plugin unload event
extern "C" void UNITY_INTERFACE_EXPORT UNITY_INTERFACE_API UnityPluginUnload()
{
s_UnityLog = nullptr;
}
extern "C" void UNITY_INTERFACE_EXPORT UNITY_INTERFACE_API GenerateLog()
{
// Output different log level messages to the Unity console
UNITY_LOG(s_UnityLog, "Regular log message");
UNITY_LOG_WARNING(s_UnityLog, "Warning log message");
UNITY_LOG_ERROR(s_UnityLog, "Error log message");
// Wrap log functions to provide native file and line number in output
NATIVE_LOG(s_UnityLog, "Regular log with native file name and line number");
NATIVE_WARNING(s_UnityLog, "Warning log with native file name and line number");
NATIVE_ERROR(s_UnityLog, "Error log with native file name and line number");
}
Note: The additional macros to embed the native file and line number in the message are a workaround for a known issue in which Unity fails to include the information when the Log function is invoked via UNITY_LOG and equivalents.