Can You Modify the `main` Function Signature in C with `unsigned` and `const` Qualifiers?

C Main Function Signature Modifiers: Understanding Unsigned and Const

The C language standard defines the main function with two valid signatures:

int main();
int main(int, char*[]);

However, the question arises: are modifications to these signatures, such as adding unsigned and const qualifiers, permissible under the C standard?

The C 98 standard, in section 3.6.1 paragraph 2, explicitly states that main cannot be overloaded. It also defines the return type of main as int, with its complete type definition being implementation-dependent. All implementations are required to support the two predefined signatures listed above.

However, the standard notably does not forbid the implementation of an environment that accepts a main function with additional qualifiers. This means that while it is not mandated by the standard, it is permissible for certain environments to extend the allowable signatures of main.

Specifically, adding const and unsigned qualifiers to the arguments of main's signature, as in the following example, may be supported in certain implementations:

int main(const unsigned int, const char* const* argv);

Therefore, while not universally guaranteed by the standard, it is possible that some compilers may allow such modifications. However, it is crucial to note that this behavior is implementation-dependent and should not be relied upon for standard-compliant code.

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