Is there any standard for the argument format of a program? [duplicate]

Question

int main(int argc, char **argv)
{}

1. Is it possible that argc equals 0?

2. Must argv[0] be the executable file's name?

3. Is there any standard for these issues?

Answer 1

1. Yes.

2. Normally yes, it could also be empty, or some other identifying string, or even NULL (see my addendum). It's also possible to change argv[0] to something else from inside the program.

3. The C (and C++) specifications.

You also missed one: The last element in argv is always NULL, meaning argv[argc] will always be NULL.

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In the C11 specification it's in §5.1.2.2.1 Program startup.

In the C++11 specification its §3.6.1 Main function.

Answer 2

1. Yes
2. No. Argv[0] don't have to exist, but if it does it is a program name, given it could be obtained.
3. I guess this is standard in C, Cpp. @JonathanLeffler linked a great answer.