Re: STL::glice vs cstdio
nmm1@cam.ac.uk wrote:
I have some code where executing some completely irrelevant calls in
cstdio causes gslice to throw a segmentation fault; a previous code
(which was buggy) caused the use of gslice to cause cerr/cout to
throw away all their output!
That sounds like severely buggy code.
class Matrix {
private:
valarray<signed char> *base;
int stride, offset;
public:
Matrix (int lwb1, int lim1, int lwb2, int lim2);
gslice_array<signed char> slice (int lwb1, int lim1, int lwb2, int
lim2);
};
The first thing I notice here is that you don't handle/prevent copying and
assignment, not even a destructor for cleanup!
Matrix::Matrix (int lwb1, int lim1, int lwb2, int lim2) {
this->base = new valarray<signed
char>((size_t)((lim1-lwb1)*(lim2-lwb2))); this->stride = lim2-lwb2;
this->offset = lwb1*this->stride+lwb2;
}
gslice_array<signed char> Matrix::slice (int lwb1, int lim1,
int lwb2, int lim2) {
static valarray<size_t> length(2), stride(2);
A function-static object like this here is just asking for trouble...
typedef class Matrix matrix;
Why?
matrix *total = NULL;
[...]
total = new matrix(-1,size+1,-1,size+1);
Why use dynamic allocation here? This is not Java!
(*total).slice(-1,0,-1,size+1) = 0;
For your info: "(*total).xyz" is usually written as "total->xyz" instead, as
you otherwise also use.
Sorry, but especially the careless use of raw pointers is a good way to
shoot yourself in the foot. Fix that and your program might run already.
Uli
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