Concatenating strings in macros - C++

问题

What's the easiest way to concatenate strings defined in macros. i.e. The pseudo code I'm looking for would be like:

#define ROOT_PATH "/home/david/"
#define INPUT_FILE_A ROOT_PATH+"data/inputA.bin"
#define INPUT_FILE_B ROOT_PATH+"data/inputB.bin"
...
#define INPUT_FILE_Z ROOT_PATH+"data/inputZ.bin"

The only way I know of is to use strcat in the code, or using the string class and then the c_str method, but it can get messy when I have lots of input files. I'd like to just use INPUT_FILE_A, etc. directly and not have lots of local variables. Is there a good way to do this?

Thanks.

回答1:

The compiler will automatically concatenate adjacent strings:

#define ROOT_PATH "/home/david/"
#define INPUT_FILE_A ROOT_PATH "data/inputA.bin"

Or more generic:

#define INPUT_FILE_DETAIL(root,x) root #x
#define INPUT_FILE(x) INPUT_FILE_DETAIL(ROOT_PATH "data/", x)

回答2:

Shell was "eating" the quotes. So, the following line had to use:

-DROOT_PATH=\"some-string"\

来源：https://stackoverflow.com/questions/1739102/concatenating-strings-in-macros-c