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The implementation shall provide unique mappings for sequences consisting of one or more nondigits or digits (6.4.2.1) followed by a period (.) and a single nondigit. The first character shall not be a digit. The implementation may ignore distinctions of
alphabetical case and restrict the mapping to eight significant characters before the period.
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- Only the first eight characters in the filename are guaranteed to be significant.
- The file only has one, nondigit character after the period in the filename.
- The case of the characters in the filename is not guaranteed to be significant.
To guarantee header file names are unique, all included files should differ (in a case insensitive manner) in their first eight characters or in their (one character) file extension.
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