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I have a custom USB cdc-acm device which sends images to the computer thanks to serial communication. As the device continuously sends data, I get this data in a separate thread in a while loop: So does data get lost? Finally and more subjective questionam I doing something really dirty with this kind of code?
Any comments or suggestions about accessing real time data through tty file? EDIT Some more precisions: I know that the device is sending frames around kbytes at a particular frame rate but the code should not depend on this framerate and be smooth at 15 fps as well as at 1 fps… no lag.
From the man pages see man 2 read: Here is your code slightly modified: I say this depends, because in some cases 0 is returned to indicate end of file.
This may or may not be treated as error. EDIT Reflecting the edits to the original question: Otherwise, do what I suggested above.
Regarding loss of data: If you want it to return 0 instead — well, this is up to the driver. One disadvantage here is that unless the driver provides some mechanism of controlling delays, there is no telling for how long the device might block subject to how quickly data arrives.futex(0x1a, FUTEX_WAIT_PRIVATE, 0, NULL) = -1 EAGAIN (Resource temporarily unavailable).
According to errno.h and various posts, 11 is EAGAIN, i.e.
"try again", because some resource was temporarily unavailable. Is there a way to determine which resource caused the fork to fail, other than increasing various system limits one by one (open file descriptors, swap space, . When I have a few programs running in KDE and do nothing, I still have Xorg and plasmashell each taking like 11 % of a CPU core.
kwin_x11 takes another 6 %. Together with other background jobs I get into the region of 12 % total system load in idle.
Feb 13, · A Passionate Techie. keep learning, keep growing. Menu and widgets. Search for: How fast can I read in /dev/ttyACM0 file? 11 Ressource Temporarily Unavailable.
So I have a couple of questions: How fast can I / . @rjp - yeah looks like there is a bug in the underlying dependency libs for file reading well not a bug, just a caveat not accounted for. I'm really not a strong c developer but it looks like the open() call on stdin will fail if it's already opened.
To work around this I believe they need to dup() the handle if the handle is a 0 or 1 and dup2() the handle back after completion.
Google Groups. Bug# linux-imagepae: FreeRADIUS EAP-TLS stopped working when kernel was updated linux-imagepae: FreeRADIUS EAP-TLS stopped working when kernel was updated.
Andreas Sundstrom: Dec 19, AM: (6, 0xbfc8, 4, 2, 0xbf, 0xbf) = -1 EAGAIN (Resource temporarily unavailable.