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Questions tagged [allocation]

Memory allocation is an operation of giving a program a block of memory.

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Why is the use of alloca() not considered good practice?

alloca() allocates memory on the stack rather than on the heap, as in the case of malloc(). So, when I return from the routine the memory is freed. So, actually this solves my problem of freeing up dynamically allocated memory. Freeing of memory…
Vaibhav
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Managing the lifetimes of garbage-collected objects

I am making a simplistic mark-and-compact garbage collector. Without going too much into details, the API it exposes is like this: /// Describes the internal structure of a managed object. pub struct Tag { ... } /// An unmanaged pointer to a…
isekaijin
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Declare slice or make slice?

In Go, what is the difference between var s []int and s := make([]int, 0)? I find that both works, but which one is better?
Wang Yi
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Freaky way of allocating two-dimensional array?

In a project, somebody pushed this line: double (*e)[n+1] = malloc((n+1) * sizeof(*e)); Which supposedly creates a two-dimensional array of (n+1)*(n+1) doubles. Supposedly, I say, because so far, nobody I asked could tell me what this does,…
User1291
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Determine size of dynamically allocated memory in C

Is there a way in C to find out the size of dynamically allocated memory? For example, after char* p = malloc (100); Is there a way to find out the size of memory associated with p?
s_itbhu
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What is the difference between [Class new] and [[Class alloc] init] in iOS?

Possible Duplicate: alloc, init, and new in Objective-C I am a little confused about [Class new] and [[Class alloc] init]. I have defined an object content using [Class new] and [[Class alloc] init]. (1). NSMutableArray *content =…
Prasad G
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Are Structs always stack allocated or sometimes heap allocated?

I was of the impression that in C#, struct elements are allocated on the stack and thus disappear when returning from a method in which they were created. But what happens if I place the struct-values in a list and return that? The elements…
Carlo V. Dango
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How to profile memory usage & performance with Instruments?

Of all the Instruments Trace Templates, I love using: Zombies to detect where an object is getting over-released, great for debugging EXEC_BAD_ACCESS errors. Leaks to detect memory leaks. Core Animation w Color Blended Layers to detect frame rate &…
ma11hew28
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Getting a stack overflow exception when declaring a large array

The following code is generating a stack overflow error for me int main(int argc, char* argv[]) { int sieve[2000000]; return 0; } How do I get around this? I am using Turbo C++ but would like to keep my code in C EDIT: Thanks for the…
Patrick McDonald
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Memory Allocation/Deallocation?

I have been looking at memory allocation lately and I am a bit confused about the basics. I haven't been able to wrap my head around the simple stuff. What does it mean to allocate memory? What happens? I would appreciated answers to any of these…
Isaac
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Escape analysis in Java

As far as I know the JVM uses escape analysis for some performance optimisations like lock coarsening and lock elision. I'm interested if there is a possibility for the JVM to decide that any particular object can be allocated on stack using escape…
Denis Bazhenov
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In what cases should I use memcpy over standard operators in C++?

When can I get better performance using memcpy or how do I benefit from using it? For example: float a[3]; float b[3]; is code: memcpy(a, b, 3*sizeof(float)); faster than this one? a[0] = b[0]; a[1] = b[1]; a[2] = b[2];
Pythagoras of Samos
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Multithreaded Memory Allocators for C/C++

I currently have heavily multi-threaded server application, and I'm shopping around for a good multi-threaded memory allocator. So far I'm torn between: Sun's umem Google's tcmalloc Intel's threading building blocks allocator Emery Berger's…
Robert Gould
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When is array allocated on stack in c#?

I've been trying to figure out when things get allocated on stack and I can't figure out how would you make array (or rather values in it) get allocated on stack; in this example: public void foo() { int bar[] = new int [10]; } 10 int structs…
morowinder
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Is it possible to remove ExecutionContext and Thread allocations when using SocketAsyncEventArgs?

If you profile a simple client application that uses SocketAsyncEventArgs, you will notice Thread and ExecutionContext allocations. The source of the allocations is SocketAsyncEventArgs.StartOperationCommon that creates a copy of the…
cao
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