[GitHub] [incubator-nuttx] patacongo opened a new issue #669: Don't use nxsem_wait_interruptible in read()/write()

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patacongo opened a new issue #669: Don't use nxsem_wait_interruptible in read()/write()
URL: https://github.com/apache/incubator-nuttx/issues/669
 
 
   In many places, nxsem_wait_uninterruptible() is used directly in directly in the read() or write() methods of character drivers.  POSIX, however, requires that these methods return EINTR if interrupted by a signal.
   
   For read(), EINTR should be returned to indicate "The read operation was terminated due to the receipt of a signal, and no data was transferred."  https://pubs.opengroup.org/onlinepubs/009695399/functions/read.html
   
   For write(), EINTR means that "The write operation was terminated due to the receipt of a signal, and no data was transferred." 
   
   POSIX also requires that the open() and close() method return EINTR if any signal is received (although I think supporting this in close() would cause issues since people seldom check the return value from close).
   
   More general, the read() and write() methods should return EINTR if a signal is received even if there is no underlying character driver.  This means that the block read/write methods of block and MTD drivers also must return EINTR if interrupt.
   

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