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Unfortunately, following code fails to compile: #define CHECK(cond) if(!(cond)) At first, I found _func_, as described here (C++11) and here (C99). Next, I searched for a way to also obtain name of current function. I know that condition expression, which is argument of my macro, can be turned into a string by using # preprocessor operator. I wanted to include as much information as possible in the message string. He currently resides in the Washington, DC area.Today, while programming in C++, I wanted to write an assert-like macro that would throw an exception when given condition is not satisfied.
He is an alumnus of the University of Wisconsin-Milwaukee and the Université d'Orléans. Mike Ash is a programmer at Plausible Labs by night, and a glider pilot by day. Tricks can help you create macros which make your code easier to write Many C programs define a macro min, for minimum, like this. However, in some situations theyĬan be incredibly useful, and, when used correctly, these tips and When a macro is called with arguments, the arguments are substituted into the macro body. If you use them, you must beĮxtremely careful not to abuse them. More information about X-macros, consult the Wikipedia article.Ĭ macros are complicated and powerful. This is an advanced and frightening technique, but it could helpĮliminate a lot of boring repetition in certain specialized cases. make the compiler treat x as the given type no matter what #define FORCETYPE(x, type) *(type *)(_typeof_(x) ) It's common to write a macro that consists of multiple statements. How the code has gone wrong, then modify your macro to make it right. Find the site where the macro is used, figure out The resulting file will generally be very largeĭue to all of the #include directives, but you'll find yourĬode near the end. In Xcode you can do this by selectingīuild->Preprocess. This means all of your macros are expanded, and youĬan see the raw C code that the compiler sees, rather than trying toĮxpand the macro in your head.
To reduce confusion, you'll want to look at the file as it appearsĪfter preprocessing. On the Design tab, in the Tools group, click Single Step. To manifest as weird compiler errors at the site where the macro is Right-click the macro in the Navigation Pane, and then click Design View. C / ANSI-C Macro Preprocessor Macro Function. Macros are code, and like any code, they will have bugs. Use Macro to check the int range : Macro Function Macro Preprocessor C / ANSI-C. Syntax for calling a function, but don't be fooled. The syntax for using a parameterized macro looks just like the the
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