Tutorial by Examples: alloc

An object can only be deallocated by delete if it was allocated by new and is not an array. If the argument to delete was not returned by new or is an array, the behavior is undefined. An object can only be deallocated by delete[] if it was allocated by new and is an array. If the argument to delet...

// The allocation functions have implementation-defined behavior when the requested size // of the allocation is zero. void *p = malloc(0);

In most object oriented languages, allocating memory for an object and initializing it is an atomic operation: // Both allocates memory and calls the constructor MyClass object = new MyClass(); In Objective-C, these are separate operations. The class methods alloc (and its historic sibling allo...

01 pointer-var usage POINTER. 01 character-field pic x(80) BASED value "Sample". ALLOCATE 1024 characters returning pointer-var ALLOCATE character-field ALLOCATE character-field INITIALIZED RETURNING pointer-var See http://open-cobol.sourceforge.net/faq/index.html#allo...

realloc is conceptually equivalent to malloc + memcpy + free on the other pointer. If the size of the space requested is zero, the behavior of realloc is implementation-defined. This is similar for all memory allocation functions that receive a size parameter of value 0. Such functions may in fact ...

Arrays in MATLAB are held as continuous blocks in memory, allocated and released automatically by MATLAB. MATLAB hides memory management operations such as resizing of an array behind easy to use syntax: a = 1:4 a = 1 2 3 4 a(5) = 10 % or alternatively a = [a, 10] a = ...

A new memory block on the heap is allocated using the new expression, which returns a pointer to the managed memory: void main() { int* a = new int; *a = 42; // dereferencing import std.stdio : writeln; writeln("a: ", *a); }

01 field-1 PIC X(80) BASED. ALLOCATE field-1 *> use field-1 FREE field-1 *> further use of field-1 will cause memory corruption

We can create Singleton class in such a way that developers are forced to used the shared instance (singleton object) instead of creating their own instances. @implementation MySingletonClass + (instancetype)sharedInstance { static MySingletonClass *_sharedInstance = nil; static dispa...

//MySingletonClass.h @interface MYSingletonClass : NSObject + (instancetype)sharedInstance; -(instancetype)init NS_UNAVAILABLE; -(instancetype)new NS_UNAVAILABLE; @end //MySingletonClass.m @implementation MySingletonClass + (instancetype)sharedInstance { static MySingleto...

Caveat: alloca is only mentioned here for the sake of completeness. It is entirely non-portable (not covered by any of the common standards) and has a number of potentially dangerous features that make it un-safe for the unaware. Modern C code should replace it with Variable Length Arrays (VLA). Ma...

Use top command to exam CPU time allocation between user space and kernel space. Explanation: 24.8 us (user space): 24.8% of CPU time is spent on user process. 0.5 sy (system): 0.5% of CPU time is spent on kernel space. ni (niceness): the ratio of CPU time spent on low priority processes. i...

var a = 11, b = 22; a = a ^ b; b = a ^ b; a = a ^ b; console.log("a = " + a + "; b = " + b);// a is now 22 and b is now 11

By default, TensorFlow pre-allocate the whole memory of the GPU card (which can causes CUDA_OUT_OF_MEMORY warning). To change this, it is possible to change the percentage of memory pre-allocated, using per_process_gpu_memory_fraction config option, A value between 0 and 1 that indicates wh...