👀 Views: 27 💬 Answers: 1 📅 Created: 2025-06-14

printf double cross-platform C

I am experiencing inconsistent output formatting for double values when using `printf` in my C application, which is compiled with GCC version 10.2 on Ubuntu 20.04 and Visual Studio 2019 on Windows 10. In particular, the output format appears to change based on the platform, leading to unexpected results that affect my application's functionality. For example, I have the following code snippet: ```c #include <stdio.h> int main() { double num1 = 12345.6789; double num2 = 0.000123456; printf("Formatted output: %.2f\n", num1); printf("Formatted output: %.5f\n", num2); return 0; } ``` On Ubuntu, I get: ``` Formatted output: 12345.68 Formatted output: 0.00012 ``` But when I run the same code on Windows, the output is: ``` Formatted output: 12345.68 Formatted output: 0.00012 ``` Both platforms show the same output for the first double, but the second one is consistently displayed with fewer digits in the output on Windows. I tried modifying the precision to different values, but I am still seeing that the output is truncated differently between platforms. I've also checked the locale settings, and they appear to be the same across both environments. I suspect this might have something to do with how floating-point arithmetic is handled or formatted differently in GCC vs MSVC, but I haven't found any definitive resources addressing this inconsistency. Is there a way to ensure that `printf` gives consistent output for double values across different platforms, or is there a specific flag I need to use in my compilation settings to address this?