Why can't compiler derive string length for array of strings?

Question

Note: This question was influenced by this answer.

The following is valid C code:

char myString[] = "This is my string";

This will allocate a string of length 18 (including the \0 character) on the stack and assign the specified value to it.

However, the following:

char myStrings[][] = {"My 1st string", "My 2nd string", "My 3rd string"};

is not valid, giving the error "array type has incomplete element type".

So I have to specify the array like this:

char myStrings[][20] = {"My 1st string", "My 2nd string", "My 3rd string"};

Where 20 is a number which is larger than my longest string.

This compiles and works as expected.

If the compiler can dynamically sense the string length when allocating a single string on the stack, why can't it do so for an array of strings?

Edit:

Just to clarify, this is not a real life programming problem I am experiencing - this is just morbid curiosity.

Answer 1

One thing is to "sense" the length of one string. Another thing is to calculate the maximum of lengths of many strings. There's a certain intuitive qualitative difference between the two. So, the language authors probably decided that the former is simple and useful, but the latter is too compilex and less useful.