[Mpi-forum] why (int)0x4c000101 ?

ÄþÄþ ¶­ dncdd at yahoo.com.cn
Sun May 27 09:42:36 CDT 2012


when I read mpich2-1.4.1 code, I saw code as follow:

Code:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18 typedef int MPI_Datatype;
#define MPI_CHAR           ((MPI_Datatype)0x4c000101)
#define MPI_SIGNED_CHAR    ((MPI_Datatype)0x4c000118)
#define MPI_UNSIGNED_CHAR  ((MPI_Datatype)0x4c000102)
#define MPI_BYTE           ((MPI_Datatype)0x4c00010d)
#define MPI_WCHAR          ((MPI_Datatype)0x4c00040e)
#define MPI_SHORT          ((MPI_Datatype)0x4c000203)
#define MPI_UNSIGNED_SHORT ((MPI_Datatype)0x4c000204)
#define MPI_INT            ((MPI_Datatype)0x4c000405)
#define MPI_UNSIGNED       ((MPI_Datatype)0x4c000406)
#define MPI_LONG           ((MPI_Datatype)0x4c000407)
#define MPI_UNSIGNED_LONG  ((MPI_Datatype)0x4c000408)
#define MPI_FLOAT          ((MPI_Datatype)0x4c00040a)
#define MPI_DOUBLE         ((MPI_Datatype)0x4c00080b)
#define MPI_LONG_DOUBLE    ((MPI_Datatype)0x4c000c0c)
#define MPI_LONG_LONG_INT  ((MPI_Datatype)0x4c000809)
#define MPI_UNSIGNED_LONG_LONG ((MPI_Datatype)0x4c000819)
#define MPI_LONG_LONG      MPI_LONG_LONG_INT 
Anyone can tell me what is the meaning of those hex values? and why does the author use them?
why do they define "MPI_CHAR" as ((MPI_Datatype)0x4c000101) instead of "char"?
thx
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mpi-forum.org/pipermail/mpi-forum/attachments/20120527/d4a943a9/attachment.html>


More information about the mpi-forum mailing list