tables initiated with pointers issues !

[Wilson014]

Hi all,

I have a serious trouble to which I found no explanation, if someone can help me this would save me really:
In my code I have lots of structures. I try to make tables of structures and then get access to elements of the structures to use them all along my code: here is an example to clarify things

typedef struct {
 
Fabric **closfabric;
 
}Network;
 

Net is part of another structure called Switch and Fabric itself is a composed structure.
I have done the following

aSwitch->net.closfabric = (Fabric **)malloc(3* sizeof(Fabric *));
 
aSwitch->net.closfabric[0] = (Fabric *)malloc(m * sizeof(Fabric ));
aSwitch->net.closfabric[1] = (Fabric *)malloc(k * sizeof(Fabric ));
aSwitch->net.closfabric[2] = (Fabric *)malloc(m * sizeof(Fabric ));
 

The compilation returns a segmentation fault because aSwitch->net.closfabric is NULL (0) .

surprisingly, in other codes the same analogy of using tables made of double pointers works perfectly with no problems and I have no problem of core dumped and NULL pointers.

I am lost and I cannot understand why am I getting this problem. It is the case whenever I try to use large dimension tables (tab *** struct for example)

Regards,

Monson

[donbock]

Is it possible that you are running out of memory, causing malloc to return NULL?

In any case, your code should deal with that possibility - every call to malloc should be followed by a snippet that tests for failure-to-allocate and deals with the situation appropriately.

[weaknessforcats]

This compiles:

Network net;
    Network* aSwitch = &net;
    int m = 3;
    int k = 3;
    aSwitch->closfabric = (Fabric **)malloc(3 * sizeof(Fabric *));
 
    aSwitch->closfabric[0] = (Fabric *)malloc(m * sizeof(Fabric));
    aSwitch->closfabric[1] = (Fabric *)malloc(k * sizeof(Fabric));
    aSwitch->closfabric[2] = (Fabric *)malloc(m * sizeof(Fabric));

but I may not clearly understand what net is.

Also, you have to be certain aSwitch is not NULL.