Question

I’m wondering whether static constant variables are thread-safe or not?

Example code snippet:

void foo(int n)
{
     static const char *a[] = {"foo","bar","egg","spam"};
     if( ... ) {
       ...
      }
}

Answer 1

To be really safe you should do

static char const*const a[]

this inhibits modification of the data and all the pointers in the table to be modified.

BTW, I prefer to write the const after the typename such that it is clear at a first glance to where the const applies, namely to the left of it.