conditional compilation ?

[Altera_Forum]

Hello.  

 I'm working with two kits of development NIOSII.   I wish to use the following conditional compilation in a common file (as user.h) :  // --- choice of board ---------------------------------- # define NIOSII_1  //#define NIOSII_2   // --- choice of MAC address ------------------------- # ifdef NIOSII_1 # ifndef FLAG_ADRESSE_MAC_ETHERNET # define FLAG_ADRESSE_MAC_ETHERNET   const char adresse_mac_ethernet[6] = {0x01, 0x02, 0x03, 0x04, 0x05, 0x06} ;  # endif // FLAG_ADRESSE_MAC_ETHERNET # endif // NIOSII_1  # ifdef NIOSII_2 # ifndef FLAG_ADRESSE_MAC_ETHERNET # define FLAG_ADRESSE_MAC_ETHERNET  const char adresse_mac_ethernet[6] = {0x11, 0x12, 0x13, 0x14, 0x15, 0x16} ;  # endif // FLAG_ADRESSE_MAC_ETHERNET # endif // NIOSII_2   The result of compilation is :  > obj/file.o *123: multiple definition of `adresse_mac_ethernet' ../file.c:218: first defined here   Does conditional compilation function ? Or do I make an error ?  Best regards   bbo

[Altera_Forum]

maybe a problem that not all files are recompiled (which include your user.h), 

after you changed your# define NIOSII_1. so you may have some .o files with old and some .o files with new definition. try to recompile all

[Altera_Forum]

Thank you for your answer 

 I have just used the command "File / Refresh" to 'refresh' my whole project. I have used the command "Project / Rebuild All".  Unfortunately, there is no change.   But I have just found this link on the ALTERA' s site :  http://www.altera.com/support/kdb/2000/01/...32000_6557.html (http://www.altera.com/support/kdb/2000/01/rd01032000_6557.html)  Could this explain my problem partly ?   I tried to use the operators# if defined(...),# if !defined(...), ... same result   Best regards.  bbo

[Altera_Forum]

If you try to# include your "user.h" file in more than one module, then you will be attempting to define multiple global variables of the same name, hence the error. If this is the case you may need to create a further condition in only one module. Perhaps something like: 

# define MAIN_MODULE# include "user.h"# undef MAIN_MODULE   then in your user.h file, something like: # ifdef MAIN_MODULE const char adresse_mac_ethernet[6] = {0x01, 0x02, 0x03, 0x04, 0x05, 0x06} ;# else extern const char adresse_mac_ethernet[];# endif  Good luck

[Altera_Forum]

yes that's it 

 adresse_mac_ethernet will be defined in all files which include your user.h, the flag FLAG_ADRESSE_MAC_ETHERNET does not prevent this.  it's better to put the definition of variables in .c files and a extern  declaration for it in the header.  eg   file: user.h ------------------------------------------------------------------------------ // --- choice of board ---------------------------------- # define NIOSII_1  //#define NIOSII_2  extern const char adresse_mac_ethernet[6];   ------------------------------------------------------------------------------   file: user.c ------------------------------------------------------------------------------# ifdef NIOSII_1# warning "******************NIOSII_1 defined" const char adresse_mac_ethernet[6] = {0x01, 0x02, 0x03, 0x04, 0x05, 0x06} ;# endif // NIOSII_1 # ifdef NIOSII_2# warning "************** NIOSII_2 defined" const char adresse_mac_ethernet[6] = {0x11, 0x12, 0x13, 0x14, 0x15, 0x16} ;# endif // NIOSII_2

[Altera_Forum]

Hi. Excuse me for the response time.  

 I had arrived at the same solution but I was not satisfied.   I thus have modify the way of writing the address : # ifdef NIOSII_1  // adresse MAC de la carte en hexadecimal# define ADRESSE_MAC "01:02:03:04:05:06" # endif # ifdef NIOSII_2  // adresse MAC de la carte en hexadecimal# define ADRESSE_MAC "11:12:13:14:15:16" # endif  and I have to create a function ether_aton(ADRESSE_MAC) :  void ether_aton(char *pt_addr_ethernet) {  int i ;  int adresse_tmp[6] ;  int *pt_int = adresse_tmp ;   // conversion de la chaine ASCII en adresse MAC 48 bits  i = sscanf(pt_addr_ethernet, " %02x:%02x:%02x:%02x:%02x:%02x",  (pt_int + 0), (pt_int + 1), (pt_int + 2),  (pt_int + 3), (pt_int + 4), (pt_int + 5)) ;   // mise au format 8 bits des composantes de l&#39;adresse MAC  for (i = 0 ; i < 6 ; i++)  {  adresse_mac_ethernet = (unsigned char)(adresse_tmp) ;  } }   Thank you for all.