Lower case letter 'l' (ell) can easily be confused with the digit '1' (one). This can be particularly confusing when indicating that an integer literal constant is a long value. This rule is similar to guideline DCL02-C. Use visually distinct identifiers.
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Search for vulnerabilities resulting from the violation of this rule on the CERT website.
Other Languages
Related Guidelines
This rule appears in the C++ Secure Coding Standard as : DCL16-CPP. Use 'L', not 'l', to indicate a long value.
This rule appears in the Java Secure Coding Standard as DCL06-J. Use 'L', not 'l', to indicate a long value.
Bibliography
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2005 AV Rule 14, "Literal suffixes shall use uppercase rather than lowercase letters."
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