Not reading in what was written out...

All, I'm hoping you can provide some help. I have opened a temporary
file, written to it, verified the correct amount was written, done
freopen() for the file to stdin, then try read the information back,
but 0 amount is being read in. I have done ferror() on the stream and
it is still 0, and freopen() != NULL.

Output from passing in 20 short values and writing them out as float
(istat is the return of fread() ):
fwrite: 10
istat: 0 ferror:0

Output from passing in 6000 short values and writing them out as float
(istat is the return of fread() ):
fwrite: 3000
istat: 2048 ferror:0
istat: 0 ferror:0


========Code========
#define FLOAT 0
#define INDIM 32768
#include <stdio.h>
#include <math.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>

main (argc,argv)
int argc;
char **argv;

{
double dfloatarray[INDIM];
float floatarray[INDIM];
int i,j,k,iop,jop,kop,nneg,abs,istat,iaccum,intype,oty pe;
int iostat,icheck;
int norm=0;
FILE *outplace;
char tempfile[] = ".dconvert_tempXXXXXX";
FILE *tempfile_fd;

/*.... Parse command line....*/

intype = FLOAT;

iaccum = 0;
if (( tempfile_fd = fdopen( mkstemp(tempfile) , "w+" )) == NULL){
fprintf(stderr,"Could not create temporary file\n");
}

while(feof(stdin) == 0){
if (intype == FLOAT) {
istat = fread(floatarray,sizeof(float),INDIM,stdin);
iaccum+=istat;
for (i=0; i<istat; i++){
dfloatarray[i] = (double) floatarray[i];
}
}

for (i=0;i<istat;i++){
floatarray[i] = (float) dfloatarray[i];
}

fprintf(stderr,"fwrite:
%d\n",fwrite(floatarray,sizeof(float),istat,tempfi le_fd) );
}

intype = FLOAT;
if(freopen(tempfile,"r+",stdin) == NULL) fprintf(stderr,"Didn't
reopen\n");

}

iaccum = 0;
while(1) {
if (intype == FLOAT) {

/*** This is where not reading the correct amount.... ***/

istat = fread(floatarray,4,INDIM,stdin);
fprintf(stderr,"istat: %d\tferror:%d\n",istat,ferror(stdin));
iaccum+=istat;
if (swapin == 1){
swapbytes(floatarray,istat,4);
}
for (i=0; i<istat; i++){
dfloatarray[i] = (double) floatarray[i];
}
}

/*....Continues on...*/




Any help is greatly appreciated! Thanks!

Josh

re: Not reading in what was written out...

joshuawilsonster@gmail.com wrote:[color=blue]
> All, I'm hoping you can provide some help. I have opened a temporary
> file, written to it, verified the correct amount was written,[/color]

Did you flush or close the temp file before attempting to read from it?
[color=blue]
> done freopen() for the file to stdin, then try read the information back,
> but 0 amount is being read in. I have done ferror() on the stream and
> it is still 0, and freopen() != NULL.
>
> ...
> ========Code========
> #define FLOAT 0
> #define INDIM 32768
> #include <stdio.h>
> #include <math.h>
> #include <stdlib.h>
> #include <string.h>
> #include <errno.h>
>
> main (argc,argv)
> int argc;
> char **argv;
>
> {
> double dfloatarray[INDIM];
> float floatarray[INDIM];[/color]

That's potentially a large amount of automatic data. On many
systems, this will blow the hardware stack.
[color=blue]
> ...
> while(feof(stdin) == 0){[/color]

This is nearly always wrong. See the clc FAQ.

--
Peter

re: Not reading in what was written out...

<joshuawilsonster@gmail.com> wrote in message
news:1149718524.579038.214150@i39g2000cwa.googlegr oups.com...[color=blue]
> All, I'm hoping you can provide some help. I have opened a temporary
> file, written to it, verified the correct amount was written, done
> freopen() for the file to stdin, then try read the information back,
> but 0 amount is being read in. I have done ferror() on the stream and
> it is still 0, and freopen() != NULL.
>
> Output from passing in 20 short values and writing them out as float
> (istat is the return of fread() ):
> fwrite: 10
> istat: 0 ferror:0
>
> Output from passing in 6000 short values and writing them out as float
> (istat is the return of fread() ):
> fwrite: 3000
> istat: 2048 ferror:0
> istat: 0 ferror:0
>
>
> ========Code========
> #define FLOAT 0
> #define INDIM 32768
> #include <stdio.h>
> #include <math.h>
> #include <stdlib.h>
> #include <string.h>
> #include <errno.h>
>
> main (argc,argv)
> int argc;
> char **argv;
>
> {
> double dfloatarray[INDIM];
> float floatarray[INDIM];
> int i,j,k,iop,jop,kop,nneg,abs,istat,iaccum,intype,oty pe;
> int iostat,icheck;
> int norm=0;
> FILE *outplace;
> char tempfile[] = ".dconvert_tempXXXXXX";
> FILE *tempfile_fd;
>
> /*.... Parse command line....*/
>
> intype = FLOAT;
>
> iaccum = 0;
> if (( tempfile_fd = fdopen( mkstemp(tempfile) , "w+" )) == NULL){
> fprintf(stderr,"Could not create temporary file\n");
> }
>
> while(feof(stdin) == 0){
> if (intype == FLOAT) {
> istat = fread(floatarray,sizeof(float),INDIM,stdin);
> iaccum+=istat;
> for (i=0; i<istat; i++){
> dfloatarray[i] = (double) floatarray[i];
> }
> }
>
> for (i=0;i<istat;i++){
> floatarray[i] = (float) dfloatarray[i];
> }
>
> fprintf(stderr,"fwrite:
> %d\n",fwrite(floatarray,sizeof(float),istat,tempfi le_fd) );
> }
>[/color]

You haven't closed the file. What you wrote may still be in a buffer
somewhere, not actually in the file on disk.
[color=blue]
> intype = FLOAT;
> if(freopen(tempfile,"r+",stdin) == NULL) fprintf(stderr,"Didn't
> reopen\n");
>
> }
>
> iaccum = 0;
> while(1) {
> if (intype == FLOAT) {
>
> /*** This is where not reading the correct amount.... ***/
>
> istat = fread(floatarray,4,INDIM,stdin);
> fprintf(stderr,"istat: %d\tferror:%d\n",istat,ferror(stdin));
> iaccum+=istat;
> if (swapin == 1){
> swapbytes(floatarray,istat,4);
> }
> for (i=0; i<istat; i++){
> dfloatarray[i] = (double) floatarray[i];
> }
> }
>
> /*....Continues on...*/
>
>
>
>
> Any help is greatly appreciated! Thanks!
>
> Josh
>[/color]
--
Fred L. Kleinschmidt
Boeing Associate Technical Fellow
Technical Architect, Software Reuse Project

re: Not reading in what was written out...

Awesome! Thanks so much for your help!