Variable argument functions

I wrote a variable argument function(va function) that requires at least one string. Then i wrote another va function that requires at least one string. How do i pass all the arguments that get passed to the second va function in a call to the first.

like...

Code:

---

void one(cont char* fmt, ...)
{
}

void two(const char* fmt, ...)
{
one(fmt, ...);
}

---

I don't think there is any way other passing them manually 1 by 1.

Well how do i do that?

Code:

---

#include <iostream>
#include <cstdarg>

using namespace std;

void two(int count, va_list va) {
        for(int i = 0; i < count; ++i) {
                cout << va_arg(va, int) << endl;
        }
}

void one(int count, ...) {
        va_list args;

        va_start(args, count);
        two(count, args);       
}

---

VC++7, Win2000.

That doesnt answer my question at all.

Ummm....you wanted to pass all the provided arguments?

The va_list syntax is an alternative method of passing a variable number of arguments.

For amusement: http://www.eskimo.com/~scs/C-faq/q15.13.html

Quote:

---

Originally posted by parksie

Code:

---

#include <iostream>
#include <cstdarg>

using namespace std;

void two(int count, va_list va) {
        for(int i = 0; i < count; ++i) {
                cout << va_arg(va, int) << endl;
        }
}

void one(int count, ...) {
        va_list args;

        va_start(args, count);
        two(count, args);       
}

---

VC++7, Win2000.

---

Don't you need a va_end() ?

Probably. Apparently all it does is reset the pointer to NULL, so I don't think it's that critical on x86 systems.

That said, even though it compiled and ran perfectly on mine, it should have been in there.

But, parksie, this way you can't call two with variable arguments anymore. The compiler won't allow it.

This should work:

Code:

---

#include <iostream>
#include <cstdarg>

using namespace std;

void two_inner(int count, va_list va) {
        for(int i = 0; i < count; ++i) {
                cout << va_arg(va, int) << endl;
        }
}

void one(int count, ...) {
        va_list args;

        va_start(args, count);
        two_inner(count, args);       
}

void two(int count, ...) {
        va_list args;

        va_start(args, count);
        two_inner(count, args);       
}

---

You can take a look at all the *printf CRT functions and _output (if you have the source) and note the similarities to parksie's and my code.

BTW the source of sprintf shows how to create a fake FILE that makes stream functions write to a memory buffer. You must be extremly careful using it though.