shared c constants in a header

Question

I want to share certain C string constants across multiple c files. The constants span multiple lines for readability:

const char *QUERY = "SELECT a,b,c "                     "FROM table..."; 

Doing above gives redefinition error for QUERY. I don't want to use macro as backspace '\' will be required after every line. I could define these in separate c file and extern the variables in h file but I feel lazy to do that.

Is there any other way to achieve this in C?

Answer 1

In some .c file, write what you've written. In the appropriate .h file, write

extern const char* QUERY; //just declaration 

Include the .h file wherever you need the constant

No other good way :) HTH

Answer 2

You could use static consts, to all intents and purposes your effect will be achieved.

myext.h:

#ifndef _MYEXT_H #define _MYEXT_H static const int myx = 245; static const unsigned long int myy = 45678; static const double myz = 3.14; #endif 

myfunc.h:

#ifndef MYFUNC_H #define MYFUNC_H void myfunc(void); #endif 

myfunc.c:

#include "myext.h" #include "myfunc.h" #include <stdio.h>  void myfunc(void) {     printf("%d\t%lu\t%f\n", myx, myy, myz); } 

myext.c:

#include "myext.h" #include "myfunc.h" #include <stdio.h>  int main() {     printf("%d\t%lu\t%f\n", myx, myy, myz);     myfunc();     return 0; }