<html><body><div style="color:#000; background-color:#fff; font-family:times new roman, new york, times, serif;font-size:12pt"><div>when I read mpich2-1.4.1 code, I saw code as follow:</div><div><br> </div><div class="bbcode_container"> <div class="bbcode_description">Code:</div> <div id="syntax-highlight-0"><div id="highlighter_731350" class="syntaxhighlighter bbcode_code cpp"><table border="0" cellpadding="0" cellspacing="0"><tbody><tr><td class="gutter"><div class="line number1 index0 alt2">1</div><div class="line number2 index1 alt1">2</div><div class="line number3 index2 alt2">3</div><div class="line number4 index3 alt1">4</div><div class="line number5 index4 alt2">5</div><div class="line number6 index5 alt1">6</div><div class="line number7 index6 alt2">7</div><div class="line number8 index7 alt1">8</div><div class="line number9 index8 alt2">9</div><div class="line number10 index9 alt1">10</div><div class="line number11 index10 alt2">11</div><div
class="line number12 index11 alt1">12</div><div class="line number13 index12 alt2">13</div><div class="line number14 index13 alt1">14</div><div class="line number15 index14 alt2">15</div><div class="line number16 index15 alt1">16</div><div class="line number17 index16 alt2">17</div><div class="line number18 index17 alt1">18</div></td><td class="code"><div class="container"><div class="line number1 index0 alt2"><code class="cpp keyword bold">typedef</code> <code class="cpp color1 bold">int</code> <code class="cpp plain">MPI_Datatype;</code></div><div class="line number2 index1 alt1"><code class="cpp preprocessor">#define MPI_CHAR ((MPI_Datatype)0x4c000101)</code></div><div class="line number3 index2 alt2"><code class="cpp preprocessor">#define MPI_SIGNED_CHAR ((MPI_Datatype)0x4c000118)</code></div><div class="line number4 index3 alt1"><code class="cpp preprocessor">#define
MPI_UNSIGNED_CHAR ((MPI_Datatype)0x4c000102)</code></div><div class="line number5 index4 alt2"><code class="cpp preprocessor">#define MPI_BYTE ((MPI_Datatype)0x4c00010d)</code></div><div class="line number6 index5 alt1"><code class="cpp preprocessor">#define MPI_WCHAR ((MPI_Datatype)0x4c00040e)</code></div><div class="line number7 index6 alt2"><code class="cpp preprocessor">#define MPI_SHORT ((MPI_Datatype)0x4c000203)</code></div><div class="line number8 index7 alt1"><code class="cpp preprocessor">#define MPI_UNSIGNED_SHORT ((MPI_Datatype)0x4c000204)</code></div><div class="line number9 index8 alt2"><code class="cpp preprocessor">#define MPI_INT ((MPI_Datatype)0x4c000405)</code></div><div class="line number10 index9
alt1"><code class="cpp preprocessor">#define MPI_UNSIGNED ((MPI_Datatype)0x4c000406)</code></div><div class="line number11 index10 alt2"><code class="cpp preprocessor">#define MPI_LONG ((MPI_Datatype)0x4c000407)</code></div><div class="line number12 index11 alt1"><code class="cpp preprocessor">#define MPI_UNSIGNED_LONG ((MPI_Datatype)0x4c000408)</code></div><div class="line number13 index12 alt2"><code class="cpp preprocessor">#define MPI_FLOAT ((MPI_Datatype)0x4c00040a)</code></div><div class="line number14 index13 alt1"><code class="cpp preprocessor">#define MPI_DOUBLE ((MPI_Datatype)0x4c00080b)</code></div><div class="line number15 index14 alt2"><code class="cpp preprocessor">#define MPI_LONG_DOUBLE
((MPI_Datatype)0x4c000c0c)</code></div><div class="line number16 index15 alt1"><code class="cpp preprocessor">#define MPI_LONG_LONG_INT ((MPI_Datatype)0x4c000809)</code></div><div class="line number17 index16 alt2"><code class="cpp preprocessor">#define MPI_UNSIGNED_LONG_LONG ((MPI_Datatype)0x4c000819)</code></div><div class="line number18 index17 alt1"><code class="cpp preprocessor">#define MPI_LONG_LONG MPI_LONG_LONG_INT</code></div></div></td></tr></tbody></table></div></div> </div> <br>Anyone can tell me what is the meaning of those hex values? and why does the author use them?<br>
why do they define "MPI_CHAR" as ((MPI_Datatype)0x4c000101) instead of "char"?<br>
thx</div></body></html>