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Section 6.2.2 of the C standard [ISO/IEC 9899:2011] states:
If the declaration of a file scope identifier for an object or a function contains the storage-class specifier
static, the identifier has internal linkage.
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CERT C++ Secure Coding Standard: DCL15-CPP. Declare file-scope objects or functions that do not need external linkage in an unnamed namespace
ISO/IEC 9899:2011 Section Section 6.2.2, "Linkages of identifiers"
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