: Nonblocking I/O readpartial read EOF Solaris FILE 256 ungetc SEGV errno stdio considered harmful p.

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1 stdio considered harmful stdio considered harmful p.

2 : Nonblocking I/O readpartial read EOF Solaris FILE 256 ungetc SEGV errno stdio considered harmful p.

3 : stdio stdio Nonblocking I/O : write ( ) signal handling stdio considered harmful p.

4 readpartial : : FILE stdio considered harmful p.

5 read : : FILE stdio considered harmful p.

6 Solaris FILE 256 : 256 : FILE unsigned char fd stdio stdio considered harmful p.

7 stdio stdio EOF ungetc SEGV stdio errno etc. stdio considered harmful p.

8 1.stdio 2. Ruby 3. Unix stdio considered harmful p.

9 stdio Ruby 1.9 : Ruby 1.8 : Unix Ruby Ruby: Unix: stdio considered harmful p.

10 stdio C FILE I/O (getc, fwrite, ungetc, etc.) (printf, scanf) I/O (popen, pclose) etc. stdio considered harmful p. 1

11 Ruby I/O (1.8 ) script IO#gets, etc. Ruby stdio kernel getc read IO#puts, etc. fwrite buffer write stdio considered harmful p. 1

12 Ruby I/O (1.9 ) script IO#gets, etc. Ruby IO#puts, etc. stdio kernel read buffer write stdio considered harmful p. 1

13 stdio : 1975 Dennis Ritchie Mike Lesk 15 W. Richard Stevens, 1992 stdio considered harmful p. 1

14 Unix stdio stdio: Dennis Ritchie 4.2BSD stdio: Chris Torek 4.4BSD NetBSD, etc. V6 V7 PWB1.0 SystemV Solaris, etc. Nonblocking I/O GNU/Linux stdio: Per Bothner stdio considered harmful p. 1

15 stdio v.s. Nonblocking I/O 1. fd Nonblocking I/O 2. fwrite 3. fflush 4. write 5. EAGAIN 6. stdio considered harmful p. 1

16 fflush (V7, ) /* */ iop->_ptr = base; iop->_cnt = BUFSIZ; if (write(fileno(iop), base, n)!= n) { /* */ iop->_flag = _IOERR; return(eof); } stdio considered harmful p. 1

17 fflush (4.4BSD, ) /* */ fp->_p = p; fp->_w = t & ( SLBF SNBF)? 0 : for (; n > 0; n -= t, p += t) { t = (*fp->_write)(fp->_cookie, (char *)p, n); if (t <= 0) { /* write */ fp->_flags = SERR; return (EOF); } } stdio considered harmful p. 1

18 fflush (glibc, ) /* partial write */ count = _IO_SYSWRITE (fp, data, to... /* */ fp->_io_write_base = fp->_io_write stdio considered harmful p. 1

19 fflush write (V7, 4.4BSD, glibc) write partial (V7) stdio considered harmful p. 1

20 Ruby 1.9 stdio write EAGAIN Ruby 1.8 stdio sync mode write EAGAIN write stdio considered harmful p. 2

21 : Ruby 1.9 write script Ruby stdio kernel buffer IO#puts, etc. write stdio considered harmful p. 2

22 : Ruby 1.8 sync mode write script IO#puts, etc. Ruby buffering mode fwrite stdio buffer write kernel sync mode write stdio considered harmful p. 2

23 : Ruby 1.9 Ruby 1.8 sync mode buffering mode socket sync mode stdio stdio considered harmful p. 2

24 readpartial/ read : (readpartial) context switch ( read ) stdio considered harmful p. 2

25 getc? or select readable = getc stdio considered harmful p. 2

26 ? stdio stdio considered harmful p. 2

27 getc? select readable getc 1byte select (1byte ) stdio considered harmful p. 2

28 FILE? V7 f->_cnt > 0 4.4BSD f->_r > 0 glibc f->_io_read_ptr!= f->_io_read_end etc. ( : 64bit Solaris ) Ruby I/O stdio considered harmful p. 2

29 read Ruby ( ) FILE read 64bit Solaris 64bit Solaris FILE : struct FILE_TAG { long pad[16]; }; stdio considered harmful p. 2

30 read Ruby bit Solaris stdio considered harmful p. 3

31 readpartial 1byte : stdio considered harmful p. 3

32 readpartial telnet.rb - port forwarder - cvs protocol - 1 etc. stdio considered harmful p. 3

33 readpartial read Ruby 1.8 FILE Ruby 1.9 stdio considered harmful p. 3

34 Solaris FILE 256 struct FILE_TAG /* needs to be b unsigned char *_base; /* the buff { ssize_t _cnt; /* number o unsigned char *_ptr; /* next cha unsigned char _flag; /* the stat unsigned char _file; /* UNIX Sys... }; 0 fd < 256 Ruby 1.9 FILE stdio considered harmful p. 3

35 Ruby 1.8 Ruby 1.8 Ruby 1.9 read errno stdio ungetc Nonblocking write Nonblocking IO#read readpartial Solaris 256 EOF popen Windows popen stdio stdio considered harmful p. 3

36 signal handling FD_SETSIZE (a C10K problem) stdio considered harmful p. 3

37 stdio Nonblocking I/O stdio considered harmful p. 3

13 I/O

13 I/O 13 I/O 98-0997-3 14 2 7 Linux OS OS OS I/O I/O TS-I/O I/O I/O TS-I/O TS-I/O 3 1 7 2 9 2.1..................... 9 2.2.................. 10 2.3 2...................... 12 2.4 Linux................... 14