Is null character included while allocating using malloc

c malloc string-length
Kraken picture Kraken · Jul 8, 2013 · Viewed 12.6k times · Source

I have been using C for quite sometime, and I have this trivial problem that I want to query about.

Say i want to create a character array that stores upto 1000 characters. Now, when I am using malloc for the same, then do I specify the size of array as 1001 character [ 1000 characters + null] or just 1000?

Also, say I came across this problem, then how could I have found the answer to this solution on my own, maybe by using some test programs. I understand the size of string is calculated without the null character, but when I am allocating the memory for the same, do I take into account the null character too?

Answer

sharptooth picture sharptooth · Jul 8, 2013

If you need that block for storing null-terminated string then yes, you need to explictly ask malloc() to allocate an extra byte for storing the null-terminator, malloc() will not do it for you otherwise. If you intend to store the string length somewhere else and so you don't need the null terminator you can get away without allocating the extra byte. Of course it's up to you whether you need null-termination for strings, just don't forget that C library string handling functions only work with null-terminated strings.

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