是否可以根据构建配置更改 Eclipse CDT 中的代码？

Question

I have a C++ project that I build for both CentOS 7 and Raspberry Pi. I have an Eclipse build configuration for compiling for CentOS and another build configuration for cross-compiling for Raspberry Pi. These both work great.

What I want is to automatically alter a line or two of code based on which build configuration I'm using. I noticed that Eclipse has a build variable called ConfigName, but I don't think that it is accessible in code. I also tried manually creating a macro for each build configuration in the project settings. However, when I try to read the macro in code I get the error that it was not declared in this scope. I really don't have much experience with macros other than the basics such as determining what OS you're compiling on.

This seems like it should be a common task that isn't difficult to figure out. Maybe I'm missing something obvious but I can't seem to find any documentation on what I'm trying to do. Is this even possible? Am I looking in the wrong direction?

Answer 1

After a lot of researching documentation and trial and error, I was able to find a solution.

In the project properties, go to C/C++ General --> Paths and Symbols --> Symbols --> GNU C++. Add a symbol for each build configuration. I added the following:

CONFIG_DEBUG
CONFIG_PI_DEBUG
CONFIG_RELEASE
CONFIG_PI_RELEASE

NOTE: Just to clarify, don't enter the above symbols together in the same place. Enter each one as a single symbol in it's respective build configuration.

Then, the code can be altered by using the preprocessor directives. I basically used the following:

#if defined(CONFIG_PI_RELEASE)
  // Raspberry Pi release code
#elif defined(CONFIG_RELEASE)
  // CentOS release code
#elif defined(CONFIG_PI_DEBUG)
  // Raspberry Pi debug code
#else
  // CentOS debug code
#endif