Re: [ECOS] fdopen() linker error

[Jonathan Larmour <jifl at eCosCentric dot com>]

Gary Thomas wrote:
> On Sun, 2004-09-26 at 03:35, Øyvind Harboe wrote:
>
> > søn, 26.09.2004 kl. 02.14 skrev Gary Thomas:
> >
> > > On Sat, 2004-09-25 at 10:49, Øyvind Harboe wrote:
> > >
> > > > > You need to add the fileio package I think
> > > > > look at the ifdef around fdopen() in
> > > > > language/c/libc/stdio/current/src/common/fopen.cxx
> > > >
> > > > Ouch, I should have figured that one out.
> > > >
> > > > Is it the intended behaviour that there is only an error link time and
> > > > not at compile time?
> > >
> > > There should be a compile time error if you build with -Wall
> > > Otherwise, C blissfully (cute, huh(1)?) will compile anything
> > > and not complain until you try to link it.
> >
> > In that case, there is a missing #if in the header files for fdopen() +
> > the other prototype next to it.
>
>
> Agreed - a generic header like "stdio.h" should not export anything
> unless it is well known to be available.  The attached patch would
> seem appropriate.  Jonathan?

One of the purposes of the fileio package is to abstract the implementation 
without being implementation specific, so this patch wouldn't be quite 
right as specific packages shouldn't be mentioned (yes there are already 
some exceptions but that's because I didn't put them there :-)).

But in any case if you look a few lines further up in the file, you'll the 
real problem is that something must be defining  (or rather implementing) 
CYGINT_ISO_STDIO_POSIX_FDFUNCS despite the implementation not being there.

The only implementor of this is CYGPKG_LIBC_STDIO_OPEN, which indeed 
doesn't do the right thing because looking at the code in 
language/c/libc/stdio/current/src/common/fopen.cxx it also depends on 
CYGPKG_LIBC_STDIO_FILEIO.

So the correct fix which I've checked in is:

Index: ChangeLog
===================================================================
RCS file: /cvs/ecos/ecos/packages/language/c/libc/stdio/current/ChangeLog,v
retrieving revision 1.30
diff -u -5 -p -r1.30 ChangeLog
--- ChangeLog	18 Aug 2004 14:11:59 -0000	1.30
+++ ChangeLog	27 Sep 2004 11:25:34 -0000
@@ -1,5 +1,10 @@
+2004-09-27  Jonathan Larmour  <jifl@eCosCentric.com>
+
+	* cdl/stdio.cdl (CYGFUN_LIBC_STDIO_OPEN_POSIX_FDFUNCS): New option,
+	to control whether or not fdopen()/fileno() are implemented.
+
 2004-08-18  Jonathan Larmour  <jifl@eCosCentric.com>

 	* cdl/stdio.cdl (CYGDAT_LIBC_STDIO_DEFAULT_CONSOLE): Only use
 	CYGDAT_IO_SERIAL_TTY_CONSOLE if set.

Index: cdl/stdio.cdl
===================================================================
RCS file: /cvs/ecos/ecos/packages/language/c/libc/stdio/current/cdl/stdio.cdl,v
retrieving revision 1.13
diff -u -5 -p -r1.13 stdio.cdl
--- cdl/stdio.cdl	18 Aug 2004 14:11:59 -0000	1.13
+++ cdl/stdio.cdl	27 Sep 2004 11:25:34 -0000
@@ -272,24 +272,33 @@ cdl_package CYGPKG_LIBC_STDIO {
             saved, and speed is improved. Note that you
             MUST have this defined if you want to use the
             scanf() family of functions."
     }

-    cdl_option CYGPKG_LIBC_STDIO_OPEN {
+    cdl_component CYGPKG_LIBC_STDIO_OPEN {
         display       "Dynamic opening/closing of files"
         requires      CYGINT_ISO_MALLOC
-        implements    CYGINT_ISO_STDIO_POSIX_FDFUNCS
         default_value { 0 != CYGINT_ISO_MALLOC }
         description   "
             fopen() and fclose() use dynamic memory
             allocation routines to allocate memory for
             new FILE structure pointers. If a malloc
             implementation is available, this option
             may be enabled to use
             fopen() and fclose(). If disabled, only the
             default console streams - stdin, stdout and
             stderr - will be available."
+
+        cdl_option CYGFUN_LIBC_STDIO_OPEN_POSIX_FDFUNCS {
+            display       "POSIX fdopen/fileno functions"
+            active_if     CYGPKG_LIBC_STDIO_FILEIO
+            implements    CYGINT_ISO_STDIO_POSIX_FDFUNCS
+            calculated    1
+            description   "This identifies to the rest of the system
+                           whether the POSIX fdopen() and
+                           fileno() functions are implemented."
+        }
     }

     cdl_option CYGDAT_LIBC_STDIO_DEFAULT_CONSOLE {
         display       "Default console device"
         flavor        data



Jifl
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