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Editorial Team
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Asked: 2026-05-30T06:58:37+00:00

Consider a simple macro: #define ECHO(x) x ECHO(foo(1, 2)) This produces the exact output

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Consider a simple macro:

#define ECHO(x) x

ECHO(foo(1, 2))

This produces the exact output we expect:

foo(1, 2)

The above example works because the parenthesis adjacent to the function call are recognized by the preprocessor.

Now consider what happens if I use a template instead of a function call:

ECHO(template<int, bool>)

This causes an error because the preprocessor interprets the template<int and the bool> as two separate arguments to the macro. The preprocessor doesn’t recognize <> for scope!

Is there anyway to use a template like this in a macro?

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1 Answer

  1. Editorial Team
    #define COMMA ,
ECHO(template<int COMMA bool>)

    A little painful, but it works.

    FWIW, if the syntax for the argument allows ()s, you don’t need the substitution, e.g.,

    ECHO((a, b))

    will work for a single argument macro but that doesn’t work in all cases (including yours).

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