Exporting float from blender and reading in c wrong value

I am writing float values from Blender using python, then read in C. For some values I get 0. If I replace that values with numbers like 2.3 or other random numbers It works. I am using struct.pack("<ffff") to write them.

Here is example value which doesn't work:

-8.881784197001252e-16, -1.700029006457271e-15, 6.106226635438361e-16, 1.0

When I opened file in hex editor I found correct number written -8.88178E-16

How can I read correct value?