[Bug libstdc++/29026] New: std::basic_istream<>::sentry() fails to catch when reading whitespace

[jimrees at itasoftware dot com]

27.6.1.1 P4 says that formatted input functions should set badbit if a call to
fetch characters from the streambuf throws an exception.

The implementation of this in bits/istream.tcc is done after the sentry is
constructed.  But the sentry's constructor may try to read whitespace, and it
is not doing any exception handling, so ios_base::badbit is not getting set in
this case.


-- 
   Summary: std::basic_istream<>::sentry() fails to catch when
reading whitespace
   Product: gcc
   Version: 4.1.1
Status: UNCONFIRMED
  Severity: normal
  Priority: P3
 Component: libstdc++
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: jimrees at itasoftware dot com
 GCC build triplet: x86_64-redhat-linux
  GCC host triplet: x86_64-redhat-linux
GCC target triplet: x86_64-redhat-linux


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29026

[Bug libstdc++/29026] std::basic_istream<>::sentry() fails to catch when reading whitespace

[jimrees at itasoftware dot com]

--- Comment #1 from jimrees at itasoftware dot com  2006-09-11 21:07 ---
Created an attachment (id=12228)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=12228&action=view)
bug reproducer program

bug reproducer, compile with g++ - any flags, but do not disable exceptions.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29026

[Bug libstdc++/29026] std::basic_istream<>::sentry() fails to catch when reading whitespace

[jimrees at itasoftware dot com]

--- Comment #2 from jimrees at itasoftware dot com  2006-09-11 21:10 ---
fyi, a "real world" example of how this comes up?   Construct a std::ifstream
using a pathname to a directory instead of a file.   Under Linux and MacOS at
least, the basic_filebuf code is happy to open such a pathname, but then will
get EISDIR when it first tries to read, and will throw an exception.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29026

[Bug libstdc++/29026] std::basic_istream<>::sentry() fails to catch when reading whitespace

[jimrees at itasoftware dot com]

--- Comment #4 from jimrees at itasoftware dot com  2006-09-11 22:23 ---
Sure, the issue sounds interesting, and the committee's resolution statement is
definitely lame.   Bug issue 309 seems to be more about what is _specified_
about sentry::sentry()'s behavior, and I don't necessarily care about that
w.r.t. this bug.

I care about 27.6.1.1 P4 (which makes no mention of sentry), and with the GNU
C++ implementation.  The fact that operator>>() happens to invoke sentry's
constructor does not make an excuse.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29026

[Bug c++/21385] New: __extension__ lost inside template

[jimrees at itasoftware dot com]

Target: x86_64-suse-linux
Configured with: ../gcc-4.0.0/configure --prefix=/ita3 --enable-languages=c,c++ 
--with-system-
zlib --enable-__cxa_atexit x86_64-suse-linux : (reconfigured) 
../gcc-4.0.0/configure --prefix=/ita3 
--enable-languages=c,c++ --with-system-zlib --enable-__cxa_atexit 
--disable-checking x86_64-
suse-linux
Thread model: posix
gcc version 4.0.0


template functions appear to erase the effect of the __extension__ keyword 
inside their definitions, 
causing "-ansi -pedantic" to produce an error instead of a warning.

Compiling the following code with "-ansi -pedantic" produces an error for the 
line in the template 
function, but not the ordinary function. 

% g++ -c -ansi -pedantic foo.cpp
foo.cpp: In function âint template_function(int) [with T = void]â:
foo.cpp:15:   instantiated from here
foo.cpp:11: error: ISO C++ forbids variable-size array

--
int ordinary_function(int dimension)
{
__extension__ int data[dimension];
return 0;
}

template
int template_function(int dimension)
{
__extension__ int data[dimension];
return 0;
}

template int template_function(int);

-- 
   Summary: __extension__ lost inside template
   Product: gcc
   Version: 4.0.0
Status: UNCONFIRMED
  Severity: minor
  Priority: P2
 Component: c++
AssignedTo: unassigned at gcc dot gnu dot org
    ReportedBy: jimrees at itasoftware dot com
CC: gcc-bugs at gcc dot gnu dot org
 GCC build triplet: x86_64-suse-linux
  GCC host triplet: x86_64-suse-linux
GCC target triplet: x86_64-suse-linux


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21385