Dear all,
I am keeping penetrating the said problem.
Although the endian-ness test is swap=1, it doesn't seems that the
garbage is aroused by the byteorder.
In c program, I try to write 1(int) + 80*4(float) + 1(int) bytes to
"gccfile.dat" ((1+80*4+1)*4 bytes). Then I tried to read this file
by IDL 6.0.
openr, lun, 'gccfile.dat',/GET_LUN ; Normal
For the INT parameters, by use of,
num = long(1) ! so it is 4 bytes.
readu, lun, num
For float parameters, by use of
mat = fltarr(80,40)
readu, lun, mat
Unfortunately, in matrix "mat", the first 138 data are right, but the
else are garbage!
BTW, the file size of "gccfile.dat" should be ((1+80*4+1)*4 bytes,
but the actual size is 1290 bytes. What are the extra 2 bytes ?
I am keeping fighting it..........
cheers,
Tony
On 8 8 , 2 10 , Nianming Zuo <nianm...@gmail.com> wrote:
> I am really frustrated by the interface between IDL6.0 and
> gcc3.4.2(Mingw32).
> The following is the test program.
>
> ***********************************************
>
> // c program, compiled by Mingw32 gcc3.4.2 on MS Windows XP
>
> #include <stdio.h>
> #include <stdlib.h>
> #include <math.h>
>
> #define col 8
> #define row 4
> #define hit 1
>
> int main()
>
> {
> float mat[row][col][hit];
> int i, j, k;
> FILE *fn;
>
> for (i=0; i<row; i++)
> {
> for (j=0; j<col; j++){
> for (k=0; k<hit; k++){
> mat[i][j][k] = i + j/2.0 +k/5.0 + (float)i/(j+1);
> }
> }
> }
>
> fn = fopen("cmat.dat", "w");
> printf("fn = %d", fn);
> if(fn == NULL)
> {
> printf("Can't open cmat.dat to write\n");
> exit(1);
> }
> fwrite(&i, sizeof(int), 1, fn);
> fwrite(mat, sizeof(float), col*row*hit, fn);
> fwrite(&j, sizeof(int), 1, fn);
> fclose(fn);
>
> exit(0);
>
> }
>
> *********************************************
> ; IDL6.0 program, on the same OS.
>
> device, retain = 2
>
> ; To test whether swap is necessary.
>
> openr,lun,'cmat.dat', /GET_LUN
> ; -- Check the record size
> RecordSize = 10000L * 4L
> RecordSize_Test = 0L
> READU, lun, RecordSize_Test
> IF ( RecordSize_Test NE RecordSize ) THEN $
> Swap = 1 $
> ELSE $
> Swap = 0
>
> ; -- Close the file
> FREE_LUN, lun
>
> print, "Swap= ", Swap
>
> cmat = fltarr(8,4)
> openr, lun, "cmat.dat",/GET_LUN,/swap_endian
>
> readu, lun, ii
> readu, lun, cmat
> readu, lun, jj
>
> print, "ii", ii
> print, "cmat", cmat
> print, "jj", jj
>
> end
>
> *************************************
> Previously, I have easily implemented the interface above on Linux/
> Mandriva 10.2 .
> But now it can not be repeated on MS Windows.
> The cpu of computer are all Intel P4 .
>
> Thanks,
>
> Tony
>
> On 8 8 , 11 52 , Nianming Zuo <nianm...@gmail.com> wrote:
>
>
>
>> Thank you, Paul, David, Mike, chl and other guys.
>> I have read the links (and other related links), and it is really
>> helpful for my puzzels.
>
>> And now, I have another problem. (The following are on MS Windows
>> XP(sp2))
>
>> IDL6.0 can not read data saved by gcc3.4. (Mingw32)
>
>> in "gccfile.dat", I saved a seriers of data, including int and float
>> type, using
>> gf = fopen("gccfile.dat", "w");
>> fwrite(NLAM, sizeof(int),1, gf);
>> //repeat this sentence to store several vars,
>> NLAM,R,D,H,ALAM0,ALAM1,DLAM , with different type.
>
>> Now, I want to read datas in "gccfile.dat", and I have tried many
>> methods.
>
>> Way 1:
>> openr, lun, "gccfile.dat", /GET_LUN
>> readu,lun,NLAM,R,D,H,ALAM0,ALAM1,DLAM
>> print, NLAM,R,D,H,ALAM0,ALAM1,DLAM
>
>> It prints strange data like 3.36641e+038, and prompts:
>> % Program caused arithmetic error: Floating underflow
>> % Program caused arithmetic error: Floating illegal operand
>
>> Way 2: (learn from this forum. THANKS :) )
>
>> openr, lun, "gccfile.dat", /GET_LUN, /SWAP_ENDIAN
>> readu,lun,NLAM,R,D,H,ALAM0,ALAM1,DLAM
>> print, NLAM,R,D,H,ALAM0,ALAM1,DLAM
>
>> It still prints the garbage!
>
>> I have tested the endian-ness things with (from Paul. Thanks):
>
>> openr,lun,'shepp.sgm', /GET_LUN ; "shepp.sgm" is my file.
>> ; -- Check the record size
>> RecordSize = 10000L * 4L
>> RecordSize_Test = 0L
>> READU, lun, RecordSize_Test
>> IF ( RecordSize_Test NE RecordSize ) THEN $
>> Swap = 1 $
>> ELSE $
>> Swap = 0
>
>> ; -- Close the file
>> FREE_LUN, lun
>
>> print, "Swap", Swap
>
>> ; The above Swap turns out 1. So swap is necessary.
>
>> Way 3:
>
>> openr, lun, "gccfile.dat", /GET_LUN ; Without /SWAP_ENDIAN
>> readu,lun,NLAM,R,D,H,ALAM0,ALAM1,DLAM
>> NLAM = SWAP_ENDIAN(NLAM)
>> print, NLAM,R,D,H,ALAM0,ALAM1,DLAM
>
>> Amazingly, NLAM (integer) is wrong, and other vars (float) are right!
>
>> I am totally confused by its behavious!
>
>> Additionally, I have tried another ways, and did't take effect.
>> byteorder, NLAM,R,D,H,ALAM0,ALAM1,DLAM, /lswap
>
>> One suggested "binread" function, but it doesn't exist in IDL6.0.
>
>> Thanks,
>
>> Tony
>
>> On 8 7 , 8 39 , Paul van Delst <Paul.vanDe...@noaa.gov> wrote:
>
>>> Nianming Zuo wrote:
>>>> Dear all,
>
>>>> I have sufferred file read/write problems between Fortran 90/95 and
>>>> IDL 6.0.
>
>>>> My Fortran compiler:
>>>> Silverfrost ftn95, Compatable for Fortran 77/90/95
>>>> http://www.silverfrost.com/12/ftn95/ftn95_feature_details.as p
>
>>>> IDL 6.0 (Interactive Data Language, RSI)
>
>>>> Both are in MS Windows XP(sp2) OS system.
>
>>>> Write data to a file by use of Fortran:
>>>> dimension dat(m, n)
>>>> !........ Manipulations..., matrix dat(m, n) is float
>>>> open(unit=11, file="file.dat", form="unformatted")
>>>> write(11) dat
>>>> !..........
>>>> ! The above are really f77 code, so I guess it is related to Compiler.
>
>>>> Read the data above by IDL6.0: (Way 1)
>>>> dat = fltarr(m,n)
>>>> openr, 1, 'file.dat'
>>>> readu, 1, b, dat, b
>
>>>> In "readu, 1, b, dat, b", the "b"s are used to skip the record area in
>>>> Fortran data format.
>>>> Unfortunately, it can not get the right result, and prompts "End of
>>>> the file"
>
>>>> I have also tried another way in IDL: (Way 2)
>>>> dat = fltarr(m,n)
>>>> openr, 1, 'file.dat' /f77_unformatted
>>>> readu, 1, dat
>
>>>> But, it prompts,
>>>> "% READU: Corrupted f77 unformatted file detected. "
>
>>>> For the above Fortran code, when it is compied by g77, IDL can read it
>>>> by Way 2.
>
>>>> So, I doubt that different compilers give different response to the
>>>> standard Fortran sentences ?
>>>> Since there is no f90_unformatted or f95_unformatted, f77/f90/f95 will
>>>> produce the same record for the "open-write" sentence.
>
>>>> Now, how can I read ftn95 compiled output data by IDL6.0 ? I have
>>>> searched this forum, but without any desirable results.
>
>>> Have a lookee at:
>
>>> http://groups.google.com/group/comp.lang.idl-pvwave/browse_t hread/thr...
>
>>> (Crikey that's a long link)
>
>>> cheers,
>
>>> paulv- -
>
>>> - -- -
>
>> - -- -
>
> - -
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