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CERT C++ Secure Coding Standard: DCL16-CPP. Use 'L', not 'l', to indicate a long value
The CERT Oracle Secure Coding Standard for Java: DCL06-J. Use 'L', not 'l', to indicate that an integer literal is of type long
Bibliography
Lockheed Martin 2005 AV Rule 14, "Literal suffixes shall use uppercase rather than lowercase letters."
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