uin64_t func_fake.return_val returns 32bit data

[vishnukumarkalidasan]

I set '(uint64_t) 0x0a0b0a0b0a0b0a0b' as return value to a func_fake(0 function for testing a 'let's say' foo_func(). but during test, the function returns 0x0a0b0a0b the msb four bytes are zero.

I did test the return_val before calling foo_func() like below. here it return whole 64bit data. but fails inside foo_func()
std::cerr << "[ ] return val = " << std::to_string(func_fake.return_val) << std::endl;

Can someone help me with this issue ?