/* c_header.h    header file that works for both C and C++ */

/* note that this works in both C and C++ because:
          1)  only C style comments are used
          2)  name mangling is turned off using  extern "C" { ... }
              in  #ifdef  --cplusplus   <-- a special name
          3)  good practice is used to be sure included just once
*/

#ifndef C_HEADER_H_   /* to only include once */
#define C_HEADER_H_   /* to only include once */

#ifdef __cplusplus    /* make it C if in C++ compiler */
  extern "C" {
#endif

#include <time.h>  /* other C header files */

void some_f(float seconds); /* types and function prototypes */
                            /* keep strictly C, not C++      */
                            
#ifdef __cplusplus  /* just closing } for C in C++ compiler  */
  }
#endif

#endif  /* C_HEADER_H_  to only include once */