Question

I have a small problem with a code written below. VS 2010 compiles it, runs and I get the predicted result. But when I tried to compile this code with Qt Creator I get this warning every time: “Expected token ‘)’ got int”. Yes, program will be run by Qt Creator, but the program will blow up. What’s wrong with this code:

#include <stdio.h>
#include <stdarg.h>
#define ARR_SIZE 2

int **getAddresses(int amount, ...)
{
    static int *arr[ARR_SIZE] = {};
    va_list vl;

    if(amount > 0)
    {
        va_start(vl, amount);
        int i;
        for(i = 0; i < amount; i++)
        {
            *(arr + sizeof(int) * i) = va_arg(vl, int*);  //This one is highlighted by the Qt Creator.
        }
        va_end(vl);
        return 0;
    }
    else
    {
        return arr;
    }
}

int main(void)
{
    int a = 3, b = 5;

    getAddresses(ARR_SIZE, &a, &b);
    printf("BEFORE: %d, %d\n", a, b);

    int **res = getAddresses(0), i;
    for(i = 0; i < ARR_SIZE; i++)
    {
        *(*(res + sizeof(int) * i)) += 5;
    }

    printf("AFTER: %d, %d\n", a, b);

    return 0;
}

Thank you for your answers beforehand.

ADDED: Qt Creator highlights this line of code *(arr + sizeof(int) * i) = va_arg(vl, int*);

Furthermore Dev++ is able to run this code without any warning and errors or crushing.

GCC is able to compile it under Fedora linux 14:

[Admin@localhost testerprog]$ gcc tester.c -o tester
[Admin@localhost testerprog]$ ls
tester  tester.c
[Admin@localhost testerprog]$ ./tester
BEFORE: 3, 5
AFTER: 8, 10
[Admin@localhost testerprog]$ 

GCC version is 4.5.1 20100924 (Red Hat 4.5.1-4)

Answer 1

— Edited, as the original post is a bit wrong, but the same line is likely the cause —

Since the error specifically mentioned finding an int instead of a closing parenthesis, I would suspect the offending line is

        *(arr + sizeof(int) * i) = va_arg(vl, int*);

And while your code is valid C / C++, I would reverse my suspicion that the VS compiler made a mistake, but offer a similar suspicion that the Qt compiler either

1. Has a bug in it and is expecting a R value, not a type.
2. Has wrapped va_arg references in some other qt_xxx style wrapper to allow proper compiling in the QT framework.

— Original post follows —

int is a keyword in C / C++ so you cannot use it as a variable safely. It seems that the line

        *(arr + sizeof(int) * i) = va_arg(vl, int*);

asks for the value of the address held by a variable, int, not the value referenced by an int pointer. Odds are that the VS compiler’s error checking isn’t as robust, leading to silent acceptance of the error.