[RTEMS Project] #4926: open() non-blocking mode. not posix compliant

[RTEMS trac]

#4926: open() non-blocking mode. not posix compliant
----------------------+--------------------
  Reporter:  yangn0   |      Owner:  (none)
      Type:  defect   |     Status:  new
  Priority:  high     |  Milestone:
 Component:  posix    |    Version:  6
  Severity:  blocker  |   Keywords:
Blocked By:           |   Blocking:
----------------------+--------------------
 {{{
 #include <rtems.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
 #include <sys/types.h>
 #include <errno.h>
 #include <sys/stat.h>
 #include <fcntl.h>
 #include <termios.h>
 #include <rtems/error.h>
 #include <string.h>

 void writeUart(int fd, int i)
 {
   char str[80];
   sprintf(str, "Hello /dev/ttyAMA%d\n", i);
   int ret = write(fd, str, strlen(str));
   if (ret <= 0)
   {
     printf("send str error. error no: %d\n", errno);
   }
 }

 rtems_task Init(
     rtems_task_argument ignored)
 {

   int ttyS[5] = {-1};
   char s[80];
   int i;

   printf("hello uart\n");

   int fd = open("/dev/ttyAMA2", O_RDWR | O_NOCTTY | O_NONBLOCK);
   if (fd == -1)
   {
     puts("fd==-1 !!");
     exit(0);
   }

   printf("fd=%d\n", fd);

   static uint16_t btstack_uart_block_read_bytes_len=1;
   char buffer[20]={'\0'};

   ssize_t bytes_read = read(fd, buffer,
 btstack_uart_block_read_bytes_len);
   printf("bytes_read=%d\n",bytes_read);
   printf("buffer=%s\n",buffer);

   printf("end uart\n");
   exit(0);
 }
 }}}

 when open() set O_NONBLOCK. read() still blocks.
 output:
 {{{
 hello uart
 fd=3
 }}}


 **Expected behavior**
 in other POSIX system(Ubuntu):

 {{{
 hello uart
 fd=3
 bytes_read=-1
 buffer=-1
 end uart
 }}}

--
Ticket URL: <http://devel.rtems.org/ticket/4926>
RTEMS Project <http://www.rtems.org/>
RTEMS Project