What does this char string related piece of C++ code do?

Question

bool check(const char *text) {
    char c;
    while (c = *text++) {
        if ((c & 0x80) && ((*text) & 0x80)) {
            return true;
        }
    }
    return false;
}

What's 0x80 and the what does the whole mysterious function do?

Answer 1

Rewriting to be less compact:

while (true)
{
    char c = *text;
    text += 1;
    if (c == '\0') // at the end of string?
        return false;
    
    int temp1 = c & 0x80;          // test MSB of c
    int temp2 = (*text) & 0x80;    // test MSB of next character
    if (temp1 != 0 && temp2 != 0)  // if both set the return true
        return true;
}

MSB means Most Significant Bit. Bit7. Zero for plain ascii characters