Should I replace _outpw() function?

Question

I have some problems when I do simulation for my Simulink program, it says > `_outpw() function not defined` Should i try to find some other function to replace it? I have put this head source (`conio.h`) in the Matlab folder, but it doesn't work.

Answer 1

The function `_outpw()` is an old DOS-based function for outputting a word to a port. This function is typically provided by the `conio.h` header file in some older compilers, primarily for DOS. If you're working in a modern environment (especially something like Simulink), this function will likely not be supported.

Here's what you should consider:

1. **Modern Systems**: If you're working with modern systems (like MATLAB's Simulink), many functions from the `conio.h` header will not be supported or relevant. Modern systems don't allow direct hardware access from user-level applications for security and stability reasons.

2. **Function Replacement**: If the purpose of `_outpw()` in your application is to interact with hardware or to provide some form of delay, you'll need to find an appropriate modern alternative. The replacement will heavily depend on what you're trying to achieve.

3. **Linking Issues**: Even if you put the `conio.h` header in the Matlab folder, it's not just about the header. The associated library that provides the implementation for `_outpw()` needs to be linked, and that's assuming MATLAB/Simulink even supports linking with that library (which is doubtful).

4. **Safety & Portability**: Direct port and memory access can be risky. On modern systems, this can lead to unpredictable behavior or even crashes. Always consider the safety and portability of your application.

In summary, yes, you should look for an alternative to the `_outpw()` function if you're working in a modern environment like Simulink. What that alternative is will depend on the specific purpose of the function in your application. If you provide more details about what you're trying to achieve with `_outpw()`, I might be able to suggest a more appropriate function or method.