QNX RTOS v4 Knowledge Base
QNX RTOS v4 Knowledge Base
| Title |
Debugging a remote application and application's devices |
| Ref. No. |
QNX.000005908 |
| Category(ies) |
Development |
| Issue |
Two nodes are full Photon "workstations" and a third node is an embedded "target" with 4Meg RAM and 4M RAM-Disk.
We have a simple program that opens /dev/ser1
fd = open("/dev/ser1", O_RDWR)
The program runs fine on the workstation, and on the target when invoked directly.
However, when invoked from a shell on node 2 through the debugger as
wd //3 testser
or equivalently
cp testser* //3
wd //3 //3/testser
wd launches testser on node 3 but the testser opens //2/dev/ser1 and not its own /dev/ser1.
Is this correct (QSSL-Expected) behavior and, if so, why?
|
| Solution |
Yes, this is "correct" behaviour. "wd //3 testser" runs testser in the equivalent mode to "on -n 3 testser", that is it runs on node 3, but with the namespace from the node it is run from (node 2), so /dev/ser1 gets resolved as //2/dev/ser2.
Work-arounds:
Change the code to open "//0/dev/ser" -- this will always get the local
serial port.
> on -n 61 fullpath /dev
/dev is //88/dev
> on -n 61 fullpath //0/dev
//0/dev is //61/dev
Start testser & wd differently:
on -f 3 -h testser
sin -n 3 -P testser
wd //3 pid_of_testser
Then, in wd, put a break at the start of main() then, have it continue. |
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