Question

I have a union with the declaration:

union test_u
{
    int i;
    char *str;
};

I am trying trying to initialize a variable with data in the “second” field, using the code:

union test_u test = {"Sample"};  // char *, not int

On attempting to compile this, I receive the error:

file.c:72:11: warning: initialization makes integer from pointer without a cast

Is it possible to initialize the variable in the same manner I have above? Shouldn’t the compiler (under C89) accept either an int to char * in the initialization?

Answer 1

With C89, only the first member of the union is initialised. So you can just change the order of variables in union:

union test_u
{
    char *str;
    int i;
};