void * (If you used your help/manual system, you would get an answer much sooner.)
malloc/calloc/realloc will return NULL
Address of the allocated area, or NULL.
I believe you can attempt to allocate as much as you want, but if you try to take more physical memory than your machine has then malloc will instead return a null pointer
The malloc function is one of a group of memory allocation functions; malloc, calloc, realloc, and free. Specifically malloc (size) returns a pointer to a new memory block of at least size bytes, suitably aligned for optimum access for any basic type, or it returns a NULL if the request cannot be satisfied.
You use a 2-D array with malloc the same way you use any other structure or scalar with malloc. The malloc library call takes a single argument of type size_t (in bytes) and returns a void* pointer to a region of memory that is suitably aligned for any supported data type. An example using the 2-D array... int *myArray[10][20]; myArray = malloc (sizeof (myArray)); if (myArray == NULL) {...exception processing...}; Note that a 2-D array is really the same as a 1-D array - its a linear region of memory - its just that the compiler does address arithmetic for you.
malloc/calloc/realloc will return NULL
Hi, The difference between new and malloc: 1.The New is a operator however malloc is a function 2.New returns the object type and there is no typecasting required. In malloc type casting should be done as it returns a void*. 3. The new operator can be overloaded however there is no over loading in C and hence Malloc can not be overloaded. 4. Operater New asks for the number of objects to be allocated however in malloc it will ask you for the number of bytes to be allocated. 5. The New operater will return you a exception of memory is not available however in malloc it will return u a NULL. 6. New is a concept for dynamically allocation in OOPS(C++) however malloc is used in C. The difference between the delete and free is as follows: 1. delete is a operator and can be overloaded however free is a function and can not be overloaded. With Regards, Shashiraja Shastry
malloc will return a 0 if memory is unable to be allocated. new on the other hand will either throw an exception or also return 0, depending on the compiler and the compiler settings.
Address of the allocated area, or NULL.
malloc is a function of the standard c library (stdlib) and it is abbreviation for memory allocate. What this function does is allocates memory in the RAM of computer to store variable data in it. You will use it whenever you need a place to store you temporary data such as an array or structure. To use malloc all you have to do is call malloc and tell it the size of the memory you want. It will then return a pointer to that memory. persumabely if it fails it returns NULL.
I believe you can attempt to allocate as much as you want, but if you try to take more physical memory than your machine has then malloc will instead return a null pointer
The malloc function is one of a group of memory allocation functions; malloc, calloc, realloc, and free. Specifically malloc (size) returns a pointer to a new memory block of at least size bytes, suitably aligned for optimum access for any basic type, or it returns a NULL if the request cannot be satisfied.
void* malloc (size_t bytes); This means that malloc takes an argument which is the size of memory to allocate and returns a pointer to that memory which has been allocated. If the return value is NULL, then the request could not be satisfied. Each call to malloc must be balanced with a corresponding call to free, to release the memory. int pa = NULL; pa = (int*) malloc (sizeof(int) * 1000); /* allocate 1000 ints */ if (pa == NULL) throw exception... ... use pa free (pa); pa = NULL;
What calloc does is: void *calloc (size_t s1, size_t s2) { size_t s= s1*s2; void *p= malloc (s); if (p && s) memset (p, 0, s); return p; }
You use a 2-D array with malloc the same way you use any other structure or scalar with malloc. The malloc library call takes a single argument of type size_t (in bytes) and returns a void* pointer to a region of memory that is suitably aligned for any supported data type. An example using the 2-D array... int *myArray[10][20]; myArray = malloc (sizeof (myArray)); if (myArray == NULL) {...exception processing...}; Note that a 2-D array is really the same as a 1-D array - its a linear region of memory - its just that the compiler does address arithmetic for you.
#include <stdlib.h> int **array1 = malloc(nrows * sizeof(int *)); for(i = 0; i < nrows; i++) array1[i] = malloc(ncolumns * sizeof(int));
Nothing, malloc does allocate memory from the heap.