Can I reuse the same buffer for subsequent itoa() calls?

Question

I'm wondering if this is safe/sanctioned usage:

char pBuf[10];
itoa(iInt, pBuf, 10);
// pBuf value gets copied elsewhere

//memset(pBuf, 0, sizeof(pBuf)); // Is this necessary?
itoa(iInt2, pBuf, 10);
// pBuf value gets copied elsewhere

Can I reuse the buffer like this?

Answer 1

Yes it is safe.

itoa will just overwrite the memory, and insert a null terminator at the end. It is this null terminator which makes it safe (assuming of course that your array is large enough)

Consider the following:

int iInt = 12345;
char pBuf[10];
itoa(iInt, pBuf, 10);

At this point, pBuf will look something like this in memory:

+---+---+---+---+---+----+-----------------------------+
| 1 | 2 | 3 | 4 | 5 | \0 | ... unintialised memory ... |
+---+---+---+---+---+----+-----------------------------+

Then you re-use pBuf:

int iInt2 = 5;    
itoa(iInt2, pBuf, 10);

Now pBuf will look like something this in memory:

+---+----+---+---+---+----+-----------------------------+
| 5 | \0 | 3 | 4 | 5 | \0 | ... unintialised memory ... |
+---+----+---+---+---+----+-----------------------------+
       ^
       |
       +---- note the null terminator