printf from spawned process

I cannot get printf to work from a spawned process. The process is created
OK and the code for it is very simple (see below)

#include<stdio.h>

int main()
{
printf(“This is the spawned process\n”);
return 0;
}

The terminal displays printf messages from the parent process but not from
the child. What am I doing wrong?

Paul.

Paul Jones <paul.jones@bnc.ox.ac.uk> wrote:

I cannot get printf to work from a spawned process. The process is created
OK and the code for it is very simple (see below)

#include<stdio.h

int main()
{
printf(“This is the spawned process\n”);
return 0;
}

The terminal displays printf messages from the parent process but not from
the child. What am I doing wrong?

Perhaps something in the parent process? :slight_smile:


Wojtek Lerch QNX Software Systems Ltd.

It works ok if I use spawnl(…) rather than spawn(…).

Paul.

“Wojtek Lerch” <wojtek_l@ottawa.com> wrote in message
news:9q72pa$627$1@nntp.qnx.com

Paul Jones <> paul.jones@bnc.ox.ac.uk> > wrote:
I cannot get printf to work from a spawned process. The process is
created
OK and the code for it is very simple (see below)

#include<stdio.h

int main()
{
printf(“This is the spawned process\n”);
return 0;
}

The terminal displays printf messages from the parent process but not
from
the child. What am I doing wrong?

Perhaps something in the parent process? > :slight_smile:


Wojtek Lerch QNX Software Systems Ltd.

Paul Jones <paul.jones@bnc.ox.ac.uk> wrote:

It works ok if I use spawnl(…) rather than spawn(…).

Could it be that there’s something wrong with how you’re using spawn() then? :slight_smile:

(What I’m really trying to say again is that it’s hard to say more
without seeing your code…)

Paul.

“Wojtek Lerch” <> wojtek_l@ottawa.com> > wrote in message
news:9q72pa$627$> 1@nntp.qnx.com> …
Paul Jones <> paul.jones@bnc.ox.ac.uk> > wrote:
I cannot get printf to work from a spawned process. The process is
created
OK and the code for it is very simple (see below)

#include<stdio.h

int main()
{
printf(“This is the spawned process\n”);
return 0;
}

The terminal displays printf messages from the parent process but not
from
the child. What am I doing wrong?

Perhaps something in the parent process? > :slight_smile:


Wojtek Lerch QNX Software Systems Ltd.


Wojtek Lerch QNX Software Systems Ltd.

Paul Jones <paul.jones@bnc.ox.ac.uk> wrote:

I cannot get printf to work from a spawned process. The process is created
OK and the code for it is very simple (see below)

#include<stdio.h

int main()
{
printf(“This is the spawned process\n”);
return 0;
}

The terminal displays printf messages from the parent process but not from
the child. What am I doing wrong?

Probably something in the parent – can you give us the spawn() call?

Most likely something with the fd_count or fd_map parameters.

-David

QNX Training Services
dagibbs@qnx.com