Dynamically declared array sizeof [duplicate]

Question

Possible Duplicate:
How to find the 'sizeof' (a pointer pointing to an array)?

I red this but it didn't help me much.

int* sum;
int size = 10;
sum = calloc(10, sizeof(int));

printf("Total length: %d", sizeof(sum)/sizeof(*sum))

The code returns 1 as expected.

I know that it would be easier to user the size variable.

My question is that is there a way of finding out this array correct size using sizeof?

Sander De Dycker · Accepted Answer · 2011-10-28 13:22:00Z

2

Other than keeping track of the size yourself (eg. the size variable in your example), there's no portable/standard way of getting the size of a dynamically allocated block of memory.

answered Oct 28, 2011 at 13:22

Sander De Dycker

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2 Comments

TGM Over a year ago

Ok so in I want to pass this memory block as a function parameter it is necessary to pass the array size too. There is no other way. Thanks!

Sander De Dycker Over a year ago

@TGM : pretty much, yes. You can make it more convenient by grouping the pointer and the size in a struct (and possibly even provide several functions to access and manipulate the data).

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