proposed change to close-stream module

[Bruno Haible]

Hi Paul and Jim,

It bothers me that in order to implement a basic functionality like the
'closeout' module, you need the __fpending module, which is not based on
POSIX but rather a case-by-case hack for various platforms.

Here is a proposed patch to lift this dependency. Instead of using
__fpending, the code in fwriteerror.c looks at the return code of
fflush. The idea is that if the stream's output buffer is nonempty
and fd=1 is an invalid file descriptor, fflush(stdout) must yield an
EBADF error.



2006-09-29  Bruno Haible  <address@hidden>

        * modules/close-stream (Depends-on): Add fwriterror. Remove fpending,
        stdbool.
        * lib/close-stream.c: Include fwriteerror.h. Don't include
        errno.h, stdbool.h, __fpending.h, unlocked-io.h.
        (close_stream): Call fwriteerror_no_ebadf.

diff -c -3 -r1.2 close-stream
*** modules/close-stream        21 Aug 2006 21:46:31 -0000      1.2
--- modules/close-stream        29 Sep 2006 14:05:54 -0000
***************
*** 7,14 ****
  m4/close-stream.m4
  
  Depends-on:
! fpending
! stdbool
  
  configure.ac:
  gl_CLOSE_STREAM
--- 7,13 ----
  m4/close-stream.m4
  
  Depends-on:
! fwriteerror
  
  configure.ac:
  gl_CLOSE_STREAM
diff -c -3 -r1.2 close-stream.c
*** lib/close-stream.c  13 Sep 2006 22:38:14 -0000      1.2
--- lib/close-stream.c  29 Sep 2006 14:05:54 -0000
***************
*** 21,34 ****
  
  #include "close-stream.h"
  
! #include <errno.h>
! #include <stdbool.h>
! 
! #include "__fpending.h"
! 
! #if USE_UNLOCKED_IO
! # include "unlocked-io.h"
! #endif
  
  /* Close STREAM.  Return 0 if successful, EOF (setting errno)
     otherwise.  A failure might set errno to 0 if the error number
--- 21,27 ----
  
  #include "close-stream.h"
  
! #include "fwriteerror.h"
  
  /* Close STREAM.  Return 0 if successful, EOF (setting errno)
     otherwise.  A failure might set errno to 0 if the error number
***************
*** 53,62 ****
  int
  close_stream (FILE *stream)
  {
-   bool some_pending = (__fpending (stream) != 0);
-   bool prev_fail = (ferror (stream) != 0);
-   bool fclose_fail = (fclose (stream) != 0);
- 
    /* Return an error indication if there was a previous failure or if
       fclose failed, with one exception: ignore an fclose failure if
       there was no previous error, no data remains to be flushed, and
--- 46,51 ----
***************
*** 64,76 ****
       is invoked like this `cp a b >&-' (i.e., with standard output
       closed) and doesn't generate any output (hence no previous error
       and nothing to be flushed).  */
! 
!   if (prev_fail || (fclose_fail && (some_pending || errno != EBADF)))
!     {
!       if (! fclose_fail)
!       errno = 0;
!       return EOF;
!     }
! 
!   return 0;
  }
--- 53,57 ----
       is invoked like this `cp a b >&-' (i.e., with standard output
       closed) and doesn't generate any output (hence no previous error
       and nothing to be flushed).  */
!   return (fwriteerror_no_ebadf (stream) < 0 ? EOF : 0);
  }