Macro note in C

1.A macro can have several spaces and tabs before #, but other characters are not allowed. Macro definition in SourceProgramSeparate line, line break is the end sign of macro definition. If a macro definition is too long and a row is not enough, you can continue the row. To continue a row, enter the "\" symbol before the keyboard returns "\". Note that the carriage return must be followed by the "\" symbol, and other symbols cannot be inserted in the middle.

2.To ensure the independence of macro calls, the macro definition as a formula should also be enclosed in brackets;

3. Use the do {} while (0) statement to include multiple statements to prevent errors. See the http://bbs.chinaunix.net/thread-1053426-2-1.html.

4. macro definition of common functions: http://wenku.baidu.com/view/702f8f1b964bcf84b9d57b60.html