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In the event that multiple statements in a macro is not bound in a do-while loop (see PRE10-C. Wrap multi-statement macros in a do-while loop), an if statement with opening and closing braces will still ensure that all statements of the macro are properly executed.
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This macro will expand correctly in a normal sequence of statements, but not as the then-clause in an if statement:
| Code Block | ||
|---|---|---|
| ||
int x, y, z, tmp; if (z == 0) SWAP( x, y); |
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Given an if statement bounded with opening and closing braces, the macro would expand as intended.
| Code Block | ||
|---|---|---|
| ||
int x, y, z, tmp; |
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if (z == 0) { |
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tmp = x; |
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x = y; |
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y = tmp; |
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} |