Hi my c code need to consider block of code depending on
#if <condition>
//code block to execute if conditions matches
#endif
Now problem is in my shell script which I run before I compile c code I set ML_ARCH=r8. I can do check in Makefile as below:
ifeq ($(ML_ARCH), r8)
endif
But for C code how to compare variable against string which is mix of char and number, in preprocessor #if
how to compare in #if condition of preprocessor for string
It is not possible to compare strings in preprocessor.
You can add something unique to r8 to make it longer and define it to a number. You could just #define r8 1, but r8 is a bit short and could be break random code.
// #define ML_ARCH r8
#define ARCH_r8 1
#define ARCH_some_other_arch 2
#define ARCH_etc 3
#define XADD_ARCH(a) ARCH_##a
#define ADD_ARCH(a) XADD_ARCH(a)
#define IS_ARCH(a) (ADD_ARCH(ML_ARCH) == ARCH_##a)
// #if XCONCAT(ARCH_, ML_ARCH) == ARCH_r8
#if IS_ARCH(r8)
Overall, consider doing -D ML_ARCH=ARCH_r8 and then just #if ML_ARCH == ARCH_r8.