Surely the UVuf is entirely supposed to give the right format to match the type of UV.

Sounds reasonable and I can't re-create the warnings in an Inline::C script - there might be more to this than I initially realized.
Here's a bit more detail regarding one of those warnings: 
XS.xs: In function 'encode_sv':
XS.xs:2449:66: warning: format '%u' expects argument of type 'unsigned
+ int', but argument 4 has type 'long long unsigned int' [-Wformat=]
 2449 |                   enc->cur += snprintf (enc->cur, IVUV_MAXCHAR
+S, "%" UVuf, UV_MAX);
      |                                                               
+   ^~~

[download]
(It's getting late over here.)

Cheers,
Rob

In reply to Re^2: [XS] : "snprintf" portability options by syphilis
in thread [XS] : "snprintf" portability options by syphilis

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.