C Reference function malloc()

The function malloc() will allocate a block of memory that is size bytes large. If the requested memory can be allocated a pointer is returned to the beginning of the memory block.

Note: the content of the received block of memory is not initialized.

Usage of malloc():

void * malloc ( size_t size );


Size of the memory block in bytes.

Return value:

If the request is successful then a pointer to the memory block is returned.
If the function failed to allocate the requested block of memory, a null pointer is returned.

Source code example of malloc():


	int main ()
		int * buffer;

		buffer = (int*) malloc (10*sizeof(int));
		if (buffer==NULL)
			printf("Error allocating memory!");
			exit (1);

		free (buffer);
		return 0;

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There are currently 5 responses to “C Reference function malloc()”

Why not let us know what you think by adding your own comment!

  1. Sonagara on June 8th, 2012:

    int x=5;
    hows it work o/p is 2

  2. adithya on July 7th, 2012:

    writing x>>1 is equivalent in writing x divided by 2 power 1. ie., the use of >> is used to indicate the division by the powers of 2, in the same way << is used to indicate the multiplication by the power of 2

  3. som on October 30th, 2012:

    how to create user defined malloc function?, what i mean is how can a user will be able to allocate a specific amount of memory.

  4. sarika keshri on March 9th, 2013:

    very good answer…

  5. andre on July 29th, 2013:

    Maybe you could use a argv[] so user can enter the size of the memory block as a parameter, and the just use

    size = atoi(argv[]);
    malloc((size_t) size);

    something like that, if I got your question right.