Thread: Seg fault

You might be trying to access an element outside of array theArray. You could print the value of each index being used before trying to access the element in that index: at least one of them might be outside the bounds of the array.

Also, and I'm not completely sure, but I think you don't need to write

Code:

struct pixel *theArray[]

as the argument to function mirror. I suspect the operators * and [] are "cancelling" each other. Maybe you could just write

Code:

struct pixel theArray

Originally Posted by stdq

I suspect the operators * and [] are "cancelling" each other.

In the context of a parameter declaration, they are not operators. Rather, this:

Code:

void mirror(struct pixel *theArray[])

is equivalent to:

Code:

void mirror(struct pixel **theArray)

i.e., theArray is declared to be a pointer to a pointer to struct pixel.

Anyway, titaniumnuke: you should explain what your mirror function is supposed to do. It would be better if you could provide the smallest and simplest compilable program that demonstrates this problem. This could be a simple program that defines struct pixel, creates your array, populates it, then calls mirror (and maybe another function that would print the array should the mirror function actually work). This way, you would show us code that we can compile and run if necessary, along with your test input (i.e., populating the array). You should also tell us your expected output (e.g., the expected print out of the array after mirror has been called on it) and actual output (in this case the segfault).

Post your main(), as in this thread -> Help with pointers and ppm images

Here are some examples of passing 2D arrays, and things which mimic 2D arrays.

Code:

void foo ( int arr[][10] ) {
}
int main ( ) {
  int a[10][10];
  foo(a);
}

Code:

void foo( int *arr[] ) {
}
int main ( ) {
  int *a[10]; // malloc each a[i]
  int **b; // malloc b and each b[i]
  foo(a);
  foo(b);
}

If you try to mix and match other combinations, it will not work!


If you're getting ANY warnings at all from your compiler, then you need to be posting your code AND your warnings.

Ignoring warnings and just posting code saying "seg fault" is just dumb. It's a complete waste of our time and yours.