extern chars?

i want to be able to use some chars in different source files, how can i do this? extern char doesnt work for me(im using Dev C/C++ in XP).

Quote:

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Originally posted by mart_man00
i want to be able to use some chars in different source files, how can i do this? extern char doesnt work for me(im using Dev C/C++ in XP).

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In the _other_ source file, are these variables declared globally? If not, they should be.

my files look like this

main.c

Code:

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extern chat input[255];

int main(int argc, char *argv[]) {

{

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other.c

Code:

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    if(input[0] = '\0')

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it doesnt see input, why?

Quote:

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Originally posted by mart_man00
my files look like this

main.c

Code:

---

extern chat input[255];

int main(int argc, char *argv[]) {

{

---

other.c

Code:

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    if(input[0] = '\0')

---

it doesnt see input, why?

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Where do you define the char input[] variable, it seem like you
just declare the vairiable but not define????

KingIII

In other.c (or preferably other.h), you must define your variable:
>char input[255];

Are you doing this?

Also, when you compile, depending on how you #incude things, you may need to link the 2 modules together. EG:

>gcc main.c other.c

so your suposed to delcare a variable twice? this doesnt overlap, id like this program to run in dos and linux.

Quote:

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Originally posted by mart_man00
so your suposed to delcare a variable twice? this doesnt overlap, id like this program to run in dos and linux.

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One call 'define' a variable and another call 'declare' a variable.
For example:

file1.c file2.c
----------------------------- --------------------------------
| //define a variable | | //declare a variable here
| char input[255]; | | extern char input[255];
| .......... | | //to access the char input[255]
|________________ | | // in file1.c
------------------------------------

KingIII

>so your suposed to delcare a variable twice?

You declare it once. The other times, you declare it as external. Assume I have a variable called var which I want to use in file1, file2 and file3, then I have to do it like this:

file1:

/* Here I declare my variable. */
int var;


file2:

/* Here I tell that my variable is an external variable, in other words, it is declared in a different file. */
extern int var;


file3:

/* Also here I tell that my variable is an external variable, in other words, it is declared in a different file. */
extern int var;