Is it possible create a "variable" header guard name in C? -


fellow programmers,

i'm new c preprocessor , have been trying create generic-like library in c (as exercise), , i've come upon little problem when creating header guards.

all preprocessor macros set can include , use headers this:

#define type int #include "myheader.h" #undef type  #define type float #include "myheader.h" #undef type  int main(void){     //do stuff     myfunc_int();      //more stuff     myfunc_float();      return 0; }

but problem appears when need include headers in more 1 file. header guards applied in case, since header can included once -for each type-, neither usual construction nor #pragma once can used.

my question is: possible create "variable" header guard work different type definitions?

when want include header various compilation units, divide header publich part plays role of header , private part plays role of *.c file, example:

#define m_concat(a, b) a##b  type m_concat(type, _min)(type a, type b);  #ifdef implement  type m_concat(type, _min)(type a, type b) {     return (a < b) ? : b; }  #endif /* implement */

then can include header multiple files, have make sure 1 file defines implement before including header: 

#define implement    // in 1 file  #define type float #include "myheader.h" #undef type  #define type int #include "myheader.h" #undef type

this file separate compilation unit, myheader.c. must take care implement function types, however. (but linker tell you, types you've missed.)


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