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POInteger to string in C without preallocated char array
 

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  1. POInteger to string in C without preallocated char array
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    <p>Please, look at the following code that just convert an unsigned int to a string (there may be some unhandled cases but it's not my question), allocating a char array in the heap and returning it, leaving the user the responsibility to free it after the use. Can you explain me why such function (and others similar) do not exist in C standard library? Yes, <code>printf("%s\n", itos(5))</code> is a memory leak, but this programming pattern is already used and is consider a good practice[1]. IMO, if such functions had existed since the dawn of C we would had little memory leaks more but <strong>tons</strong> of buffer overflows less!</p> <pre><code>#include &lt;stdio.h&gt; #include &lt;stdlib.h&gt; #include &lt;math.h&gt; char* itos(unsigned int value) { int string_l = (value == 0) ? 1 : (int)log10(value) + 1; char *string = malloc((string_l + 1) * sizeof(char)); int residual = value; int it; for (it = string_l - 1; it &gt;= 0; it--) { int digit; digit = residual % 10; residual = residual / 10; string[it] = '0' + digit; } string[string_l] = '\0'; return string; } int main(void) { char* string = itos(534534345); printf("%s\n", string); free(string); return 0; } </code></pre> <p>[1] <a href="http://www.opengroup.org/onlinepubs/009695399/functions/getaddrinfo.html" rel="nofollow noreferrer">http://www.opengroup.org/onlinepubs/009695399/functions/getaddrinfo.html</a></p> <p>EDIT:</p> <p>Habbie's answer:</p> <pre><code>char *string; asprintf(&amp;string, "%d", 155); printf("%s\n", string); free(string); </code></pre>
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    1. COare you aware of asprintf? It's in GNU libc, FreeBSD, OpenBSD and some others. see http://linux.die.net/man/3/asprintf
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    2. COYour reference to justify small memory leaks as being considered good practice is a description of the `getaddrinfo` and `freeaddrinfo` functions. I don't get it.
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      1. POInteger to string in C without preallocated char array
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    3. CO@torak: wait , i'm not justifying memory leaks at all. `printf("%s\n", itos(55));` is a memory leak because I want to print the string "55", but I can't free the memory allocated for "55" because I lost the pointer to it. I just wanted to say that `getaddrinfo()` allocate space that the user have to deallocate explicitly with `freeaddrinfo()`, and that exactly the way i'd like to operate for such a trivial thing such a conversion int->string, without wasting memory such as declaring `char string[MAX_INT_DIGITS]` for "1". Read my edit.
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