C undefined reference to InetPtonW

The error "undefined reference to InetPtonW" occurs when your C code references the InetPtonW function, but the linker cannot find the corresponding implementation of this function.

The InetPtonW function is a Windows-specific function for converting an IPv4 or IPv6 address from its text representation to a binary format. To use this function in your C code, you need to link your program with the required Windows library that contains the implementation of InetPtonW.

In order to resolve the "undefined reference" error, follow these steps:

1. Include the Required Header:
   In your C code, make sure to include the necessary Windows header that declares the InetPtonW function. The required header is <Ws2tcpip.h>. Add the following line at the top of your code:

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   #include <Ws2tcpip.h>
   
   

2. Link with the Windows Library:
   On Windows, you need to link your program with the Windows Socket Library (Ws2_32.lib), which contains the implementation of InetPtonW. To do this, add the library to your project's linker options.

   If you're using a build system like gcc or MinGW, you can specify the library in the command line using the -l flag:

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   gcc yourfile.c -o yourprogram.exe -lws2_32
   
   

   If you're using an IDE like Visual Studio, you can add the library to your project's properties by navigating to "Project Properties" > "Configuration Properties" > "Linker" > "Input" > "Additional Dependencies" and add "ws2_32.lib" to the list.

3. Ensure Windows Target:
   Make sure that you are building your C code for the Windows target. If you're using a cross-compiler or targeting a different platform, the InetPtonW function may not be available.

By following these steps, the "undefined reference to InetPtonW" error should be resolved, and your C code should be able to use the InetPtonW function to convert IP addresses.