The type void signifies the pointer can reference the memory regardless of type. The second parameter is the integer to fill with the pointer allocation. Note that this parameter is received as an integer argument that later gets converted to the character when memory filling is required.
This conversion ensures that functions keep only 8 bits needed from the integer parameter. Else it might consume more memory than needed. The third parameter represents the given size of the memory block that has to be filled. When the pointer references the memory location to fill this space, it tells nothing about how much memory it should fill.
Therefore, the main purpose of passing this parameter is to ensure proper and positive size so that memory allocation doesn't suffer memory loss. You might receive nothing back from the memset if you expect to get what you gave to these functions.
You might only expect to get some output after the function turns around and returns a pointer with the same memory address passed when you try to call the memset function. To use memset in your program, the first thing you need to do is to include the string header file in your program, as shown below. Once the string library of C is included in your program, you need nothing more.
You can easily access the memset function directly. As previously discussed, while programming in C, it is always a best practice to have tight control and maintenance of memory while allocating memory and initializing it. In case you don't initialize immediately, other dedicated functions like strcpy might come into use.
Proper usage of strcpy involves a new block memory allocation method where a copy of a string is kept aside before actually using it. Since it is not initialized, it might need to be declared first before actually using strcpy. In such cases, memset is very suitable to fill the block or clear them out initially. Consider the example given below to understand why is memset used.
In general, memset is a great tool to be considered while working with C and memory allocation methods. In simple words, if you can't initialize it, memset it.
So far, you have to see all the relevant examples and use cases for a particular memset instance. But, to understand better, you need to look at multiple examples that will be discussed as an application of memset.
Consider the below examples that describes its applications. It is quite clear from the previous as well as this example how memset handles initialization. In the code given above, you can see how memset acts with the variable defining the size of the character array or string. After using the memset function, you see five repeated characters of H from the given string. This example is similar to the previous one with a catchy hook.
It is important to understand the variations of the same programs with different usage techniques of memset. In the above example, you can see that only the offset location is being filled.
In this example, the only difference is the last five characters filled with H since you can see that the memory location or initialization of address has already been done. There are times when you can opt to use memset to zero for array initialization. If the object is non copyable, then also the behavior of the function is undefined. Using the sizeof function to get the actual array size and setting 0 integral value by memset function. Explanation: In the above program, 2 arrays, i. Function sizeof is used to find the actual size of the array.
In order to traverse the array and print its value on a console, for loop is used. So the results are undefined as you can see in the output. In practice, the GCC compiler, when it is optimizing, will generate clever code for that, usually unrolling and inlining it actually, it is often a builtin, so GCC can generate very clever code for it.
One can say that memset doesn't care about the data type and just sets all bytes to zero. Description- The memset function shall copy c converted to an unsigned char into each of the first n bytes of the object pointed to by s. Here for the above function , the memset shall return s value. If you add any files,it will delete all existing files related to this question- questions only answer remains unchanged.
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