Aaaagh!! passing addr of struct

[jdeejay]

Can someone please help with this seemingly easy task. I have a struct and want to call another function that can manipulate the data within the struct.

I have a main where the struct is.
I have written a file to have the function.
And then I have written a mylib.h which is incl in each.

I can do this with an int to the function and manipulate it, but can't seem to get the syntax correct for a struct. Is there anything special about struct vs an int or char when doing this? What am I missing. I have ??? where I keep having the problem. I have written exactly as seen in two books, but still no.

**********************************
/* mylib.h ---my test header file */
void fnA (???)

*********************************
/* misfunc.c -- contains function declarations */

#include "mylib.h"

void fnA( ??? )
{
//do some stuff here;
}

********************************
/* test.c -- contains the main program */

#include "mylib.h"

typedef struct mystruct
{
//my structure schtuff
}Config;

main ()
{
Config myconfig = {/*initializers*/};
fnA ( &myconfig );

}


Thanks,
J

 

[Zyrenthian]

fnA should look like

void fnA( struct Config& cfg )
{
//do some stuff here;
}

Matt

 

[Zyrenthian]

However, you may be seeing problems because the function fnA does not know what Config is. Make sure the delclaration of the struct is before the function declaration.

Matt

 

[jdeejay]

Matt,

Thanks for the help. I put that in for both the misfunc.c and the mylib.h entry but I am still getting errors.

when compiling test.c - refers to the mylib.h file and says "parse error before '&'" also warnings that struct Config is declared inside parameter list and that its scope is only there which is probably not what I want.

Same messages appear when compiling the misfunc.c file.

In reference to your second post--the struct declaration is above the main just as appears. correct? I don't have to add the fnA prototype again to the test.c do I. I thought that was the purpose of the #include "mylib.h"

Any ideas?

John

 

[holt1]

Move the structure definition from test.c to mylib.h. Put it above the fnA prototype. Change "struct Config& cfg" to "struct Config* cfg" in the parameter lists. Still use "&" when calling the function though. I beleive the "*" is used to declare a pointer varible as well as dereferncing a pointer. The "&" is used to get the address of a non-pointer variable.

 

[holt1]

I'm not sure that you need "struct" in the parameter list either. It may not make a difference. Try "Config* cfg" in your parameter lists instead.

Good Luck!

 

[jdeejay]

Thanks,

That last response fixed the problem (after doing your first suggestion).

J