Namespaces
Variants
Views
Actions

malloc

From cppreference.com
< c‎ | memory
Revision as of 12:10, 4 February 2014 by P12 (Talk | contribs)

Defined in header <stdlib.h>
void* malloc( 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 free().

Example

#include <stdio.h>   
#include <stdlib.h> 
 
int main() 
{
 
    /* Allocate an array of four integers. */
    int *pa = malloc(4*sizeof(int));
    if (pa == NULL) {
       printf("malloc() failed in file %s at line # %d", __FILE__,__LINE__);
       exit(1);
    }
 
    /* Initialize array A with values. */
    for (int ndx=0; ndx < 4; ndx++)
        pa[ndx] = ndx;
 
    /* Print one of the array elements. */
    printf("pa[3] = %d\n", pa[3]);
 
    /* Deallocate array pa. */
    free(pa);
    return 0;
}

Output:

A[3] = 3

See also