<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="yiv967623907bbcode_container"> <div class="yiv967623907bbcode_description">Code:</div> <div id="yiv967623907syntax-highlight-0"><div id="yiv967623907highlighter_731350" class="yiv967623907syntaxhighlighter yiv967623907bbcode_code yiv967623907cpp"><table border="0" cellpadding="0" cellspacing="0"><tbody><tr><td class="yiv967623907gutter"><div class="yiv967623907line yiv967623907number1 yiv967623907index0 yiv967623907alt2">1</div><div class="yiv967623907line yiv967623907number2 yiv967623907index1 yiv967623907alt1">2</div><div class="yiv967623907line yiv967623907number3 yiv967623907index2 yiv967623907alt2">3</div><div class="yiv967623907line yiv967623907number4 yiv967623907index3 yiv967623907alt1">4</div><div class="yiv967623907line
yiv967623907number5 yiv967623907index4 yiv967623907alt2">5</div><div class="yiv967623907line yiv967623907number6 yiv967623907index5 yiv967623907alt1">6</div><div class="yiv967623907line yiv967623907number7 yiv967623907index6 yiv967623907alt2">7</div><div class="yiv967623907line yiv967623907number8 yiv967623907index7 yiv967623907alt1">8</div><div class="yiv967623907line yiv967623907number9 yiv967623907index8 yiv967623907alt2">9</div><div class="yiv967623907line yiv967623907number10 yiv967623907index9 yiv967623907alt1">10</div><div class="yiv967623907line yiv967623907number11 yiv967623907index10 yiv967623907alt2">11</div><div class="yiv967623907line yiv967623907number12 yiv967623907index11 yiv967623907alt1">12</div><div class="yiv967623907line yiv967623907number13 yiv967623907index12 yiv967623907alt2">13</div><div class="yiv967623907line yiv967623907number14 yiv967623907index13 yiv967623907alt1">14</div><div class="yiv967623907line yiv967623907number15
yiv967623907index14 yiv967623907alt2">15</div><div class="yiv967623907line yiv967623907number16 yiv967623907index15 yiv967623907alt1">16</div><div class="yiv967623907line yiv967623907number17 yiv967623907index16 yiv967623907alt2">17</div><div class="yiv967623907line yiv967623907number18 yiv967623907index17 yiv967623907alt1">18</div></td><td class="yiv967623907code"><div class="yiv967623907container"><div class="yiv967623907line yiv967623907number1 yiv967623907index0 yiv967623907alt2"><code class="yiv967623907cpp yiv967623907keyword yiv967623907bold">typedef</code> <code class="yiv967623907cpp yiv967623907color1 yiv967623907bold">int</code> <code class="yiv967623907cpp yiv967623907plain">MPI_Datatype;</code></div><div class="yiv967623907line yiv967623907number2 yiv967623907index1 yiv967623907alt1"><code class="yiv967623907cpp yiv967623907preprocessor">#define MPI_CHAR
((MPI_Datatype)0x4c000101)</code></div><div class="yiv967623907line yiv967623907number3 yiv967623907index2 yiv967623907alt2"><code class="yiv967623907cpp yiv967623907preprocessor">#define MPI_SIGNED_CHAR ((MPI_Datatype)0x4c000118)</code></div><div class="yiv967623907line yiv967623907number4 yiv967623907index3 yiv967623907alt1"><code class="yiv967623907cpp yiv967623907preprocessor">#define
MPI_UNSIGNED_CHAR ((MPI_Datatype)0x4c000102)</code></div><div class="yiv967623907line yiv967623907number5 yiv967623907index4 yiv967623907alt2"><code class="yiv967623907cpp yiv967623907preprocessor">#define MPI_BYTE ((MPI_Datatype)0x4c00010d)</code></div><div class="yiv967623907line yiv967623907number6 yiv967623907index5 yiv967623907alt1"><code class="yiv967623907cpp yiv967623907preprocessor">#define MPI_WCHAR ((MPI_Datatype)0x4c00040e)</code></div><div class="yiv967623907line yiv967623907number7 yiv967623907index6 yiv967623907alt2"><code class="yiv967623907cpp yiv967623907preprocessor">#define MPI_SHORT ((MPI_Datatype)0x4c000203)</code></div><div class="yiv967623907line yiv967623907number8 yiv967623907index7 yiv967623907alt1"><code class="yiv967623907cpp
yiv967623907preprocessor">#define MPI_UNSIGNED_SHORT ((MPI_Datatype)0x4c000204)</code></div><div class="yiv967623907line yiv967623907number9 yiv967623907index8 yiv967623907alt2"><code class="yiv967623907cpp yiv967623907preprocessor">#define MPI_INT ((MPI_Datatype)0x4c000405)</code></div><div class="yiv967623907line yiv967623907number10 yiv967623907index9
yiv967623907alt1"><code class="yiv967623907cpp yiv967623907preprocessor">#define MPI_UNSIGNED ((MPI_Datatype)0x4c000406)</code></div><div class="yiv967623907line yiv967623907number11 yiv967623907index10 yiv967623907alt2"><code class="yiv967623907cpp yiv967623907preprocessor">#define MPI_LONG ((MPI_Datatype)0x4c000407)</code></div><div class="yiv967623907line yiv967623907number12 yiv967623907index11 yiv967623907alt1"><code class="yiv967623907cpp yiv967623907preprocessor">#define MPI_UNSIGNED_LONG ((MPI_Datatype)0x4c000408)</code></div><div class="yiv967623907line yiv967623907number13 yiv967623907index12 yiv967623907alt2"><code class="yiv967623907cpp yiv967623907preprocessor">#define MPI_FLOAT ((MPI_Datatype)0x4c00040a)</code></div><div class="yiv967623907line yiv967623907number14 yiv967623907index13
yiv967623907alt1"><code class="yiv967623907cpp yiv967623907preprocessor">#define MPI_DOUBLE ((MPI_Datatype)0x4c00080b)</code></div><div class="yiv967623907line yiv967623907number15 yiv967623907index14 yiv967623907alt2"><code class="yiv967623907cpp yiv967623907preprocessor">#define MPI_LONG_DOUBLE
((MPI_Datatype)0x4c000c0c)</code></div><div class="yiv967623907line yiv967623907number16 yiv967623907index15 yiv967623907alt1"><code class="yiv967623907cpp yiv967623907preprocessor">#define MPI_LONG_LONG_INT ((MPI_Datatype)0x4c000809)</code></div><div class="yiv967623907line yiv967623907number17 yiv967623907index16 yiv967623907alt2"><code class="yiv967623907cpp yiv967623907preprocessor">#define MPI_UNSIGNED_LONG_LONG ((MPI_Datatype)0x4c000819)</code></div><div class="yiv967623907line yiv967623907number18 yiv967623907index17 yiv967623907alt1"><code class="yiv967623907cpp yiv967623907preprocessor">#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>