How to Solve the Compile Error: "strncpy: This function or variable may be unsafe"

MFC projects generated using the wizard may encounter a compile error when using the strncpy function. The error message suggests disabling deprecation warnings by adding the _CRT_SECURE_NO_WARNINGS flag.

Incorrect Preprocessor Flag

Despite adding _CRT_NONSTDC_NO_WARNINGS to the Preprocessor Definitions, the error persists in one project. This is because the correct flag to disable warnings for the strncpy function is _CRT_SECURE_NO_WARNINGS.

Difference Between Projects

The difference between the проекты заключается в нескольких различных параметрах, заданных в мастере. The second project likely has the _CRT_SECURE_NO_WARNINGS flag enabled in the preprocessor definitions.

Solution

To resolve the error, add the following line to the Preprocessor Definitions section of the Configuration Properties:

_CRT_SECURE_NO_WARNINGS

This flag disables deprecation warnings for functions that have been marked as unsafe by the compiler.

Example

Here's an example of how to add the flag in Visual Studio:

1. Open the project's Property Pages (right-click the project and select "Properties").
2. Navigate to Configuration Properties > C/C > Preprocessor.
3. In the Preprocessor Definitions field, add the flag: _CRT_SECURE_NO_WARNINGS.
4. Click "OK" to save the changes.

After adding the flag, the compile error associated with strncpy should be resolved.