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std::malloc

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< cpp‎ | memory‎ | c
Revision as of 07:53, 17 September 2013 by Nate (Talk | contribs)

 
 
 
 
Defined in header <cstdlib>
void* malloc( std::size_t size );

Allocates size bytes of uninitialized storage.

If allocation succeeds, returns a pointer to the lowest (first) byte in the allocated memory block that is suitably aligned for any object type.

If size is zero, the behavior is implementation defined (null pointer may be returned, or some non-null pointer may be returned that may not be used to access storage)

Contents

Parameters

size - number of bytes to allocate

Return value

Pointer to the beginning of newly allocated memory or null pointer if error has occurred. The pointer must be deallocated with std::free().

Notes

This function does not call constructors or initialize memory in any way. Thus preferred method of memory allocation is new expression.

Example

#include <cstdlib>
#include <iostream>
 
int main()
{
    // Allocate an array of 4 integers
    int *array = static_cast<int *>(std::malloc(4 * sizeof(int)));
 
    if (array != nullptr) {
        for (int arrayIdx = 0; arrayIdx < 4; ++arrayIdx) {
            array[arrayIdx] = 2 * ( arrayIdx + 1 );
        }
 
        for (int arrayIdx = 0; arrayIdx < 4; ++arrayIdx) {
            std::cout << "Array item " << ( arrayIdx + 1 ) << " = " << array[arrayIdx] << '\n';
        }
        std::free(array);
    }
}

Possible output:

Array item 1 = 2
Array item 2 = 4
Array item 3 = 6
Array item 4 = 8


See also

allocation functions
(function) [edit]
obtains uninitialized storage
(function template) [edit]
C documentation for malloc