C# version of __FUNCTION__ macro

Question

Does anyone has a good solution for a C# version of the C++ __FUNCTION__ macro? The compiler does not seem to like it.

Solution 1

Try using this instead.

System.Reflection.MethodBase.GetCurrentMethod().Name

C# doesn't have __LINE__ or __FUNCTION__ macros like C++ but there are equivalents

Solution 2

What I currently use is a function like this:

using System.Diagnostics;

public string __Function() {
    StackTrace stackTrace = new StackTrace();
    return stackTrace.GetFrame(1).GetMethod().Name;
}

When I need __FUNCTION__, I just call the __Function() instead. For example:

Debug.Assert(false, __Function() + ": Unhandled option");

Of course this solution uses reflection too, but it is the best option I can find. Since I only use it for Debugging (not Tracing in release builds) the performance hit is not important.

I guess what I should do is create debug functions and tag them with

[ Conditional("Debug") ]

instead, but I haven't got around to that.

Thanks to Jeff Mastry for his solution to this.

Solution 3

Unfortunately there is no equivalent version of that macro in C#. I don't consider the GetCurrentMethodName() solution equivalent to the C++ __FUNCTION__ macro. Namely becase the C++ version is a compile time computation of the name. For C# this is a runtime calculation and incurs a performance hit.

I'm not making any assumtions about the severity of the cost but there is one

Solution 4

The following should work, although it will be evaluated at runtime instead of during compilation.

System.Reflection.MethodBase.GetCurrentMethod().Name

Solution 5

I use this:

public static string CallerName([CallerMemberName] string callerName = "")
{
    return callerName;
}

Usage example:

s_log.DebugFormat("{0}", CallerName());

The down side of using it is that every time you want to print the caller name, you need to jump to the function ==> time consuming & performance hit! So, I use it for debugging perpose and if I need to print also in production code, I usually inline the function name into the log.Debug, e.g. :

s_log.Debug("CallerName");

HTH..

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Comments

[Filip Frącz]

True, it would be nice to have a compile-time solution. For my purpose reflection is quite sufficient.

[Raymond]

As this one is top and accepted, can you/someone add: System.Reflection.MethodBase.GetCurrentMethod().ToString() will yield the params too so its not ambiguous in the face of overloads and that System.Reflection.MethodBase.GetCurrentMethod().DeclaringTyp‌​e.ToString() to give the C name (&namespace)

[Iain Ballard]

there is a #line metadata-macro, which is used to give debugging information. The compiler will inject them for you, so be careful using it in normal code!

[jjxtra]

Fails with async