Converting a double to a long, then back to double?

Question

Does Converting a double to a long, then back to double, guarantees keeping the exact value to the left of the decimal point?

EDIT: Working with C++: Conversion is as follows:

double d_var = func();
long l_var = (long)d_var;
d_var = (double)l_var;

Answer 1

For every programming language I have worked with it will keep the value to the left of the decimal point.