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<h3 class="section">4.3 Identifiers</h3>

     <ul>
<li><cite>Which additional multibyte characters may appear in identifiers
and their correspondence to universal character names (C99 6.4.2).</cite>

     <p>See <a href="../cpp/Implementation_002ddefined-behavior.html#Implementation_002ddefined-behavior">Implementation-defined behavior</a>.

     <li><cite>The number of significant initial characters in an identifier
(C90 6.1.2, C90 and C99 5.2.4.1, C99 6.4.2).</cite>

     <p>For internal names, all characters are significant.  For external names,
the number of significant characters are defined by the linker; for
almost all targets, all characters are significant.

     <li><cite>Whether case distinctions are significant in an identifier with
external linkage (C90 6.1.2).</cite>

     <p>This is a property of the linker.  C99 requires that case distinctions
are always significant in identifiers with external linkage and
systems without this property are not supported by GCC.

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