Very Computer

by **Huntres** » Fri, 09 Nov 2001 00:47:12

Hi all,
I am writing a c program on a unix machine.
I am using popen to open a pipe to run a shell script and get the result
back. I do this several times with success. However, one of the times, I
always get back an error that says "broken pipe". Does anyone know what
causes this and how to fix it?

Sample code...
This one works fine.

strcpy(cmd, "date +%m/%d/%Y");
if ((ptmp = popen(cmd, "r")) != NULL)
{
fgets(dateDumpReceived, 11, ptmp);
pclose(ptmp);
}
else
strcpy(dateReceived, "00/00/0000");

The code that breaks is this...
sprintf(cmd, "isInDB %s %s", customerName, orderNumber);
if ((ptmp = popen(cmd, "r")) != NULL)
{
fgets(response, 1, ptmp);
pclose(ptmp);
}
if (strncmp(response, "Y", 1) != 0)
{
printf("Fatal Error: Customer not found in DB!.\n");
return 1;
}

Looks the same to me...but the second one gives me the "broken pipe"
message. If it matters, the second bit there actually appears first in
the full code.

Can anyone help...?

Thanks!
~kaeli~

by **Joe Halpi** » Fri, 09 Nov 2001 01:09:57

> The code that breaks is this...
> sprintf(cmd, "isInDB %s %s", customerName, orderNumber);
> if ((ptmp = popen(cmd, "r")) != NULL)
> {
> fgets(response, 1, ptmp);
> pclose(ptmp);
> }
> if (strncmp(response, "Y", 1) != 0)
> {
> printf("Fatal Error: Customer not found in DB!.\n");
> return 1;
> }

Are you sure that isInDB is in the PATH variable of the shell that
gets popen'd? What happens if you put the full path of the command in
cmd? eg

sprintf(cmd, "/full/path/isInDB %s %s", customerName, orderNumber);

Joe
--
Remember Flight 93

by **Huntres** » Fri, 09 Nov 2001 04:48:53

> > The code that breaks is this...
> > sprintf(cmd, "isInDB %s %s", customerName, orderNumber);
> > if ((ptmp = popen(cmd, "r")) != NULL)
> > {
> > fgets(response, 1, ptmp);
> > pclose(ptmp);
> > }
> > if (strncmp(response, "Y", 1) != 0)
> > {
> > printf("Fatal Error: Customer not found in DB!.\n");
> > return 1;
> > }

> Are you sure that isInDB is in the PATH variable of the shell that
> gets popen'd? What happens if you put the full path of the command in
> cmd? eg

> sprintf(cmd, "/full/path/isInDB %s %s", customerName, orderNumber);

Actually, the full path is there. I just shortened it for here 'cuz it's
really long. :)
It actually works now with no intervention from me, so I guess it was a
machine error of some kind. I am still curious as to what would cause
it...

~kaeli~

Very Computer

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