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/* * Swaps two values. * Requires tmp variable to be defined. */ #define SWAP(x, y) \ tmp = x; \ x = y; \ y = tmp |
This macro will expand expands correctly in a normal sequence of statements , but not as the then clause in an if statement:
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int x, y, z, tmp; if (z == 0) SWAP( x, y); |
It will expand expands to the following, which is certainly not what the programmer intended:
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