Is it really necessary to use `unsigned char` to hold binary data as in some libraries which work on character encoding or binary buffers? To make sense of my question, have a look at the code below -

    char c[5], d[5];
    c[0] = 0xF0;
    c[1] = 0xA4;
    c[2] = 0xAD;
    c[3] = 0xA2;
    c[4] = &#39;\0&#39;;
    
    printf(&quot;%s\n&quot;, c);
    memcpy(d, c, 5);
    printf(&quot;%s\n&quot;, d);

both the `printf&#39;s` output `&#150370;` correctly, where `f0 a4 ad a2` is the encoding for the Unicode code-point `U+24B62 (&#150370;)` in hex.

Even `memcpy` also correctly copied the bits held by a char.

What reasoning could possibly advocate the use of `unsigned char` instead of a `plain char`?

In other related questions `unsigned char` is highlighted because it is the only (byte/smallest) data type which is guaranteed to have no padding by the C-specification. But as the above example showed, the output doesn&#39;t seem to be affected by any padding as such.

I have used VC++ Express 2010 and MinGW to compile the above. Although VC gave the warning 

`warning C4309: &#39;=&#39; : truncation of constant value`

the output doesn&#39;t seems to reflect that.

P.S. This could be marked a possible duplicate of https://stackoverflow.com/questions/653336/should-a-buffer-of-bytes-be-signed-or-unsigned-char-buffer?rq=1 but my intent is different. I am asking why something which seems to be working as fine with `char` should be typed `unsigned char`?

**Update:** To quote from N3337, 

`Section 3.9 Types`

&gt; 2 For any object (other than a base-class subobject) of trivially
&gt; copyable type T, whether or not the object holds a valid value of type
&gt; T, the underlying bytes (1.7) making up the object can be copied into
&gt; an array of char or unsigned char. If the content of the array of char
&gt; or unsigned char is copied back into the object, the object shall
&gt; subsequently hold its original value.

In view of the above fact and that my original example was on Intel machine where `char` defaults to `signed char`, am still not convinced if `unsigned char` should be preferred over `char`.

Anything else?

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C/C++ Why to use unsigned char for binary data?