declare and initialize variables in a header file

alaios · 09-03-2005, 06:04 PM

I have the following two files
1.c
1.h
The 1.c includes the 1.h

In the 1.h i have tried to declare and initialize some variables
oid IpInReceives[]={ 1, 3, 6, 1, 2, 1, 4, 3};

When i have tried to compile it
I get this message
/tmp/cc9OXXPK.o(.data+0x0): In function `snmp_fetch_oid_value':
/home/alaios/code/monitor.c:23: multiple definition of `myoida'
/tmp/ccW5SXVh.o(.data+0x0):/home/alaios/code/3threads.c:10: first defined here
collect2: ld returned 1 exit status

I have searched using the grep and nowhere else this variable is initializes.. I have also noticed that when i removed tha declaration and the initialization from the header file to the .c file.. Everything gone smoothly...
Why?

Hivemind · 09-03-2005, 06:26 PM

If you want an array to be global and if you want to be able to change the contents of the elements, declare it extern in the header. Then define it in a source file. Like this:

Code:

extern int array[]; /* in globals.h" */

Code:

#include "globals.h"
int array[] = {1, 2, 3}; /* in globals.c */

If the global array is supposed to be non-changing, you don't need to declare it extern, just declare static const in the header file and skip the definition in the c-file.

Code:

static const int an_array_that_never_changes_the_values_of_its_elements[] = {1, 2, 3}; /* in globals.h */

alaios · 09-03-2005, 07:59 PM

Thx i have tried the static const but it returns me now the compiler thw following warning
warning: passing arg 2 of `snmp_fetch_oid_value' discards qualifiers from pointer target type

Hivemind · 09-04-2005, 04:25 AM

You're not supplying very much information. Show me exactly how the variable is the declared, show me the function and show me how you pass the variable. I'm sure it can be condensed into a small test program that you can post here (inside [ code ] [ /code ] tags).