Newton's method

[Francisco J Molina]

In gsl_multiroot_function the prototype of the member function f 
is 
int f (gsl_vector * x, void * p, _matrix * f ).

I am trying to avoid the use of the function
gsl_vector_get ( x, 0 );
and supstitute it with 
pX = x->data;
pX [ 0 ];

Is this safe? Is the stride of x always 1?
Thank you.