02-05-2018
The second process, cmd2, will be able to read the standard output from cmd1 You should not need to know the PID.
It's all a bit theoretical at the moment. Can you explain what you really want to achieve?
Something like ls -l | more is a simple example of this. The output from ls -l (excluding errors) is passed to more which displays the output, pausing with a prompt when it believes it has written a screenful. The shell transfers the input for the more to be reading from the output of the ls rather than from the keyboard or whatever else standard input is defined as.
I'm sure we can explain this with a better example of what you are trying to do overall.
Kind regards,
Robin
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LEARN ABOUT SUSE
wimax_msg_alloc
WIMAX_MSG_ALLOC(9) Linux Networking WIMAX_MSG_ALLOC(9)
NAME
wimax_msg_alloc - Create a new skb for sending a message to userspace
SYNOPSIS
struct sk_buff * wimax_msg_alloc(struct wimax_dev * wimax_dev, const char * pipe_name, const void * msg, size_t size, gfp_t gfp_flags);
ARGUMENTS
wimax_dev
WiMAX device descriptor
pipe_name
"named pipe" the message will be sent to
msg
pointer to the message data to send
size
size of the message to send (in bytes), including the header.
gfp_flags
flags for memory allocation.
RETURNS
0 if ok, negative errno code on error
DESCRIPTION
Allocates an skb that will contain the message to send to user space over the messaging pipe and initializes it, copying the payload.
Once this call is done, you can deliver it with wimax_msg_send.
IMPORTANT
Don't use skb_push/skb_pull/skb_reserve on the skb, as wimax_msg_send depends on skb->data being placed at the beginning of the user
message.
Unlike other WiMAX stack calls, this call can be used way early, even before wimax_dev_add is called, as long as the wimax_dev->net_dev
pointer is set to point to a proper net_dev. This is so that drivers can use it early in case they need to send stuff around or communicate
with user space.
COPYRIGHT
Kernel Hackers Manual 2.6. July 2010 WIMAX_MSG_ALLOC(9)