Databases
StackOverflow2013
Postsdbo
POHow can you flush a write using a file descriptor?
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POHow can you flush a write using a file descriptor?
    primarykey
    data
    text
    <blockquote> <p>It turns out this whole misunderstanding of the open() versus fopen() stems from a buggy I2C driver in the Linux 2.6.14 kernel on an ARM. Backporting a working bit bashed driver solved the root cause of the problem I was trying to address here.</p> </blockquote> <p>I'm trying to figure out an issue with a serial device driver in Linux (I2C). It appears that by adding timed OS pauses (sleeps) between writes and reads on the device things work ... (much) better. </p> <blockquote> <p>Aside: <em>The nature of I2C is that each byte read or written by the master is acknowledged by the device on the other end of the wire (slave) - the pauses improving things encourage me to think of the driver as working asynchronously - something that I can't reconcile with how the bus works. Anyhoo ...</em></p> </blockquote> <p>I'd either like to <strong>flush</strong> the write to be sure (rather than using fixed duration pause), <strong><em>or</em></strong> somehow test that the write/read transaction has <strong>completed</strong> in an multi-threaded friendly way. </p> <p>The trouble with using <code>fflush(fd);</code> is that it requires 'fd' to be stream pointer (not a file descriptor) i.e.</p> <pre><code>FILE * fd = fopen("filename","r+"); ... // do read and writes fflush(fd); </code></pre> <p>My problem is that I require the use of the <code>ioctl()</code>, which doesn't use a stream pointer. i.e.</p> <pre><code>int fd = open("filename",O_RDWR); ioctl(fd,...); </code></pre> <p>Suggestions?</p>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. USIharob Al Asimi
    1. USJamie
    plurals
    1. This table or related slice is empty.
    1. PL
      singulars
      1. LTLinked
    2. PL
      singulars
      1. LTLinked
    3. PL
      singulars
      1. LTLinked
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    2. PO
      singulars
      1. PTAnswer
    3. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POHow can you flush a write using a file descriptor?
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. POHow can you flush a write using a file descriptor?
      1. This table or related slice is empty.
      1. VTUpMod
    3. VO
      singulars
      1. POHow can you flush a write using a file descriptor?
      1. This table or related slice is empty.
      1. VTUpMod
    1. COIn user-land code, the write() function is automatically non-buffered. You don't need to flush it -- it is self-flushing. Indeed, unless you use special system calls, it is also synchronous with device driver.
      singulars
      1. POHow can you flush a write using a file descriptor?
      1. USJonathan Leffler
    2. COIf you are writing a kernel-level module, the rules may be somewhat different, but then you should probably be using the file descriptor i/o and not standard (file pointer) i/o.
      singulars
      1. POHow can you flush a write using a file descriptor?
      1. USJonathan Leffler
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload