[ECOS] read and write to standerd IO

[Satoshi Sasaki]

Hello there,

I'm examining Man Machine Interface using Serial I/F on MBX860.
I want to use read() and write() command, for compatibility
with other OS.

My understanding is as follows.

STDIN fd    : 0
STDOUT fd   : 1
STDERROR fd : 2

read() failed if the following programs are executed.
test_prog() is executed as a thread.

int test_prog()
{
  char tmpbuf[5];

  write(1,"XXXX",4);
  read(0,&tmpbuf,4);

  tmpbuf[4]=0;
  printf("%s\n",(char *)&tmpbuf);

  return(0);
}

The following program works correct.

int test_prog()
{
  int testfd;
  char tmpbuf[5];
  testfd=open("/dev/ser1",3,0666);

  write(testfd,"XXXX",4);
  read(testfd,&tmpbuf,4);

  tmpbuf[4]=0;
  printf("fd=%d,%s\n",testfd,(char *)&tmpbuf);
  close (testfd);

  return(0);
}

Testfd was 3 at this time.

Can I use standard input(fd number 0)?

Or is it necessary to call open() again from a user program?
(Like the 2nd program)
In this case, doesn't it compete with the device which has already
opend for STDIO?

Or is STDIO input not opened ?

Thank you

---------------
Satoshi Sasaki
sasaki@info.kobelco.co.jp (Kobe Japan) 



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