PUBLISHED ON: MAY 28, 2022
Difference Between Malloc and Calloc
Introduction
The primary difference between malloc and calloc() is that calloc() requires two parameters rather than the one needed by malloc (). The C programming language includes both malloc() and calloc() procedures for dynamic memory allocation and de-allocation during runtime.
Let us first comprehend the notion of dynamic memory allocation before learning about malloc() and calloc() procedures. The technique of allocating computer memory for the execution of programmes and processes is known as memory allocation. When the amount of memory space required for the programme and process is unknown, we employ dynamic allocation strategies.
Malloc()
The malloc function allocates a memory block in bytes. The user must specify the block size that is required for usage.
The malloc function asks memory allocation from the system's RAM, and if the request is granted (i.e., the malloc function returns a pointer to the first block of memory), it returns a pointer to the first block of memory. It yields a void pointer, which implies it may be given to any kind of pointer.
If the malloc function is unable to allocate the needed amount of memory, it returns NULL.
Calloc()
The calloc function is identical to the malloc function, with the exception that it takes two parameters, while malloc() just requires one.
The calloc function, unlike malloc, takes two parameters instead of one (). Otherwise, it behaves similarly to malloc (). The allocated region is instantly initialised to zero when calloc is defined for the purpose of creating a block of memory.
This is not the case with malloc, which does not allow access to the allocated memory block or its contents. The key feature of the C calloc function is best described by this malloc and calloc distinction.
Comparison Table Between Malloc() and Calloc()
| Malloc() |
Calloc() |
- Malloc() allocates a single byte block of the needed memory.
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- Calloc() dynamically allocates numerous blocks of memory to any process or application.
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- void *malloc(size_t size);
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- void *calloc(size_t num, size_t size)
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- The malloc() method fails to initialise and free the memory it has been allocated. It has a random trash value in it, and the allocated memory item can't be changed.
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- The calloc() method sets the memory previously allocated to zero.
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- Malloc() works rapidly and without pauses.
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- Because it first sets the value of the pointer to ZERO, the calloc () is rather sluggish and takes longer to finish. However, this latency is insignificant and has no impact on the program's performance.
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- The malloc() method allocates memory from the available heap to the specified size.
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- The calloc() method allocates memory that is the same size as 'num *size'.
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- Malloc is the term given to memory allocation.
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- Calloc stands for "contiguous allocation."
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- If the request is met, void *malloc(size t n) will return a reference to a value of n bytes of uninitialized storage. If the request is unsuccessful, it will return a NULL value. The results will remain undefined if the memory space allocated by malloc() is exceeded.
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- Void *calloc(size_t n, size_t size) will return a pointer to allocate enough free space of an array of n objects; which will be of a pre-defined and specified size. The NULL value is assigned in case the request fails to be satisfied. Here, the storage is again initialised to zero.
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Conclusion
Both the malloc and calloc functions are used to allocate memory and have advantages and disadvantages. For example, malloc is faster than calloc. Furthermore, whereas calloc allocates memory and initialises memory region with ZERO, malloc is simpler to use because it only requires one parameter. When variable initialization is more critical to you, though, you should use calloc.
