Problem opening/closing more Informix C-isam files

[Stefan Smeets]

Hi,
I have the following problem in Informix C-Isam under Windows 2000, with
Microsoft Visual C/C++:
I open f.e. 5 isam files together.
Then I close these 5 files.
The program gives an exception after opening the 3th file.
It gives also an exception when I close the second file, if two files are
open.
Is there a problem with the c-isam library, or with the compilation option ?
I use Informix C-Isam v.7.25 (mentioned on CD-ROM).
Here the code of testing:

#include <stdio.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <io.h>
#include <errno.h>
#include <isam.h>

main()
{
int i,j;
int fd[2048];
char fname[256];
int RecordSize=128;
struct keydesc sKey; // Pointer to key descriptor

sKey.k_flags = ISNODUPS;
sKey.k_nparts = 1;
sKey.k_part[0].kp_start = 0;
sKey.k_part[0].kp_leng = 10;
sKey.k_part[0].kp_type = CHARTYPE;

for (i=1;i<100i++) {
sprintf(fname,"c:\\temp\\file%04d",i);
if ((fd[i] = isbuild(fname,RecordSize,&sKey,ISINOUT+ISEXCLLOCK) ) < 0) {
fprintf(stderr, "Error opening is file %s - errno: %d iserrno:
%d\n",fname, errno, iserrno);
j=i-1;
i=2048;
}
}
for (i=1;i<j;i++) {
if (isclose(fd[i]) < 0) {
fprintf(stderr, "Error closing file %d\n",i);
}
}

printf("Program ended\n");
exit(0);
}

Thanks for the answers,
Stefan

[Jonathan Leffler]

Stefan Smeets wrote:

> Hi,
> I have the following problem in Informix C-Isam under Windows 2000, with
> Microsoft Visual C/C++:
> I open f.e. 5 isam files together.
> Then I close these 5 files.
> The program gives an exception after opening the 3th file.
> It gives also an exception when I close the second file, if two files are
> open.
> Is there a problem with the c-isam library, or with the compilation option ?
> I use Informix C-Isam v.7.25 (mentioned on CD-ROM).
> Here the code of testing:
>
> #include <stdio.h>
> #include <fcntl.h>
> #include <sys/types.h>
> #include <sys/stat.h>
> #include <io.h>
> #include <errno.h>
> #include <isam.h>
>
> main()

Should be int main(void) on most systems - MS Win2K might have other
views.

> {
> int i,j;
> int fd[2048];
> char fname[256];
> int RecordSize=128;
> struct keydesc sKey; // Pointer to key descriptor
>
> sKey.k_flags = ISNODUPS;
> sKey.k_nparts = 1;
> sKey.k_part[0].kp_start = 0;
> sKey.k_part[0].kp_leng = 10;
> sKey.k_part[0].kp_type = CHARTYPE;
>
> for (i=1;i<100i++) {
> sprintf(fname,"c:\\temp\\file%04d",i);
> if ((fd[i] = isbuild(fname,RecordSize,&sKey,ISINOUT+ISEXCLLOCK) ) < 0) {
> fprintf(stderr, "Error opening is file %s - errno: %d iserrno:
> %d\n",fname, errno, iserrno);
> j=i-1;
> i=2048;
> }
> }

That's some pretty weird logic. You start as if you're going to run i
from 1 to 99, but then you play with i setting it 2048, so the loop
terminates after one cycle - creating one file. You've stashed the
ISAM file descriptor into fd[1], and set j to 0.

> for (i=1;i<j;i++) {
> if (isclose(fd[i]) < 0) {
> fprintf(stderr, "Error closing file %d\n",i);
> }
> }

Here you run from 1 up to a value less than 0 (j), or do no iterations
of the loop. This is also excessively weird. It also bears no
resemblance to the circumstances you describe in your outline.

So, you'd probably best send the code that really does crash - this
might or might not crash, but it doesn't open 5 files. Or have you
solved the problem already?

I doubt if you'll be able to open 2048 C-ISAM files - I don't think
C-ISAM has that many slots in its internal table of C-ISAM file
descriptors.

> printf("Program ended\n");
> exit(0);
> }

On most systems, you'd do as well with return(0) instead of exit(0).
You should include <stdlib.h> to get the declaration of exit().

--
Jonathan Leffler #include <disclaimer.h>
Email: [email]jleffler@earthlink.net[/email], [email]jleffler@us.ibm.com[/email]
Guardian of DBD::Informix v2003.04 -- [url]http://dbi.perl.org/[/url]

[Scott Burns]

Jonathan Leffler wrote:

> Stefan Smeets wrote:

<SNIP>

>

>>
>> for (i=1;i<100i++) {
>> sprintf(fname,"c:\\temp\\file%04d",i);
>> if ((fd[i] = isbuild(fname,RecordSize,&sKey,ISINOUT+ISEXCLLOCK) ) <
>> 0) {
>> fprintf(stderr, "Error opening is file %s - errno: %d iserrno:
>> %d\n",fname, errno, iserrno);
>> j=i-1;
>> i=2048;
>> }
>> }

>
>
> That's some pretty weird logic. You start as if you're going to run i
> from 1 to 99, but then you play with i setting it 2048, so the loop
> terminates after one cycle - creating one file. You've stashed the
> ISAM file descriptor into fd[1], and set j to 0.

Follow the brackets. Let's reformat:
for (i=1;i<100i++) /* ; missing? */
{
sprintf(fname,"c:\\temp\\file%04d",i);
if ((fd[i] = isbuild(fname,RecordSize,&sKey,ISINOUT+ISEXCLLOCK) ) < 0)
{
/* On error, print the error, set to i to 2048 to end the loop, then set
j to the actual number we _did_ open */
fprintf(stderr, "Error opening is file %s - errno: %d iserrno:
%d\n",fname, errno, iserrno);
j=i-1;
i=2048;
}
}

>

>> for (i=1;i<j;i++) {
>> if (isclose(fd[i]) < 0) {
>> fprintf(stderr, "Error closing file %d\n",i);
>> }
>> }

>
>
> Here you run from 1 up to a value less than 0 (j), or do no iterations
> of the loop.

<SNIP>

for i = 1, i less than the number we succeeded in opening, add one each
itteration...

I think you read that last post just a little quickly...

--
Scott Burns
Mirrabooka Systems

Tel +61 7 3857 7899
Fax +61 7 3857 1368

[Jonathan Leffler]

Scott Burns wrote:

> Jonathan Leffler wrote:
>

>> Stefan Smeets wrote:

>[...major snippage...]
> for i = 1, i less than the number we succeeded in opening, add one each
> itteration...
>
> I think you read that last post just a little quickly...

OK - the layout was less than stellar; I probably did misread it. I
withdraw all comments.

I'm not going to spend more time on it, I'm afraid. I spend a lot of
time looking at unreadable code, and I don't like it (doubly not when
it's my own code that I now deem unreadable - fortunately, that's not
my main concern at the moment, but it does happen).

--
Jonathan Leffler #include <disclaimer.h>
Email: [email]jleffler@earthlink.net[/email], [email]jleffler@us.ibm.com[/email]
Guardian of DBD::Informix v2003.04 -- [url]http://dbi.perl.org/[/url]