Hi,
there seems to be a problem with manipulators in g++/gcc-2.96. First
some are not defined in std:: and second, when using this manipulators
on streams, they give strange results. A small test-programm to show
it:
#include <cstdlib>
#include <iostream>
int main(int argc, char **argv)
{
//std::cout << std::fixed << std::showpoint << 0.123456789 << std::endl;
std::cout << std::ios::fixed << std::ios::showpoint << 0.123456789 << std::endl;
exit(EXIT_SUCCESS);
}
Compiling and running this programm gives the following result:
~$ ./a.out
40962560.123457
~$
Anyone got an idea whats going wrong here ?
Thanks in advance for your help.
Darius.
16  1931 
"Darius.Moos AT esigma-systems DOT de" <pf*********@gmx.de> wrote in message
news:c6************@ID-193014.news.uni-berlin.de... Hi,
there seems to be a problem with manipulators in g++/gcc-2.96. First
some are not defined in std:: and second, when using this manipulators
on streams, they give strange results. A small test-programm to show
it:
#include <cstdlib>
#include <iostream>
int main(int argc, char **argv)
{
//std::cout << std::fixed << std::showpoint << 0.123456789 <<
std::endl; std::cout << std::ios::fixed << std::ios::showpoint << 0.123456789
<< std::endl;
exit(EXIT_SUCCESS);
}
Compiling and running this programm gives the following result:
~$ ./a.out
40962560.123457
~$
Anyone got an idea whats going wrong here ?
Thanks in advance for your help.
Darius.
I think you'll get more idea if you run the following
std::cout << std::ios::fixed << '|' << std::ios::showpoint << '|'
<< 0.123456789 << std::endl;
One of your manipulators is being output as the number 4096256 (presumably
its an address).
Upgrade to gcc v3 would be my advice.
john
On Tue, 27 Apr 2004 13:07:18 +0200, John Harrison wrote: "Darius.Moos AT esigma-systems DOT de" <pf*********@gmx.de> wrote in
message news:c6************@ID-193014.news.uni-berlin.de... there seems to be a problem with manipulators in g++/gcc-2.96. First
some are not defined in std:: and second, when using this manipulators
on streams, they give strange results. A small test-programm to show
[...] I think you'll get more idea if you run the following
std::cout << std::ios::fixed << '|' << std::ios::showpoint <<
'|'
<< 0.123456789 << std::endl;
Gives:
~$ ./a.out
4096|256|0.123457
~$
One of your manipulators is being output as the number 4096256
(presumably its an address).
They seem to be part of an enumeration.
Upgrade to gcc v3 would be my advice.
Unfortunately this is no option as long as the current project runs.
Darius.
"Darius.Moos AT esigma-systems DOT de" <pf*********@gmx.de> wrote in message
news:c6************@ID-193014.news.uni-berlin.de... On Tue, 27 Apr 2004 13:07:18 +0200, John Harrison wrote: "Darius.Moos AT esigma-systems DOT de" <pf*********@gmx.de> wrote in
message news:c6************@ID-193014.news.uni-berlin.de... there seems to be a problem with manipulators in g++/gcc-2.96. First
some are not defined in std:: and second, when using this manipulators
on streams, they give strange results. A small test-programm to show
[...] I think you'll get more idea if you run the following
std::cout << std::ios::fixed << '|' << std::ios::showpoint <<
'|'
<< 0.123456789 << std::endl;
Gives:
~$ ./a.out
4096|256|0.123457
~$
One of your manipulators is being output as the number 4096256
(presumably its an address).
They seem to be part of an enumeration.
Upgrade to gcc v3 would be my advice.
Unfortunately this is no option as long as the current project runs.
Darius.
What happens when you try
std::cout << std::fixed << std::showpoint << 0.123456789 <<
std::endl;
Thinking about it that is the correct code.
john
On Tue, 27 Apr 2004 14:05:43 +0200, John Harrison wrote: > "Darius.Moos AT esigma-systems DOT de" <pf*********@gmx.de> wrote in
> message news:c6************@ID-193014.news.uni-berlin.de...
>> there seems to be a problem with manipulators in g++/gcc-2.96. First
>> some are not defined in std:: and second, when using this
>> manipulators on streams, they give strange results. A small
>> test-programm to show
[...] What happens when you try
std::cout << std::fixed << std::showpoint << 0.123456789 <<
std::endl;
Thinking about it that is the correct code.
They are not defined nor are they declared in std::, so the compiler
throws an appropriate error-message.
I could workaround the problem by (un)setting flags on the stream; just
wanted to use manipulators in the first place.
Darius.
Darius.Moos AT esigma-systems DOT de wrote: Hi,
there seems to be a problem with manipulators in g++/gcc-2.96. First
some are not defined in std:: and second, when using this manipulators
on streams, they give strange results. A small test-programm to show
it:
Yes, I've seen it also. Somehow under g++-2.9x when you output
certain manipulators to the stream you get their internal
enum values sent to the stream instead of these manipulators
acting, how bizzare!
The only two solutions I found were
a) upgrade to g++ 3.x, it's fixed in there
b) use cout.setf(...) instead -- it works fine.
HTH,
- J.
On Tue, 27 Apr 2004 14:14:19 +0200, "Darius.Moos AT esigma-systems DOT
de" <pf*********@gmx.de> wrote: On Tue, 27 Apr 2004 14:05:43 +0200, John Harrison wrote: > "Darius.Moos AT esigma-systems DOT de" <pf*********@gmx.de> wrote in
> message news:c6************@ID-193014.news.uni-berlin.de...
>> there seems to be a problem with manipulators in g++/gcc-2.96. First
>> some are not defined in std:: and second, when using this
>> manipulators on streams, they give strange results. A small
>> test-programm to show
[...] What happens when you try
std::cout << std::fixed << std::showpoint << 0.123456789 <<
std::endl;
Thinking about it that is the correct code.
They are not defined nor are they declared in std::, so the compiler
throws an appropriate error-message.
I could workaround the problem by (un)setting flags on the stream; just
wanted to use manipulators in the first place.
Have you included <iomanip> (or <iomanip.h> with older compilers)? You
have to include the relevent header or things aren't defined...
Tom
--
C++ FAQ: http://www.parashift.com/c++-faq-lite/
C FAQ: http://www.eskimo.com/~scs/C-faq/top.html
On Tue, 27 Apr 2004 14:46:05 +0200, tom_usenet wrote: On Tue, 27 Apr 2004 14:14:19 +0200, "Darius.Moos AT esigma-systems DOT
de" <pf*********@gmx.de> wrote:On Tue, 27 Apr 2004 14:05:43 +0200, John Harrison wrote: What happens when you try
std::cout << std::fixed << std::showpoint << 0.123456789 <<
std::endl;
Thinking about it that is the correct code.
They are not defined nor are they declared in std::, so the compiler
throws an appropriate error-message.
I could workaround the problem by (un)setting flags on the stream; just
wanted to use manipulators in the first place.
Have you included <iomanip> (or <iomanip.h> with older compilers)? You
have to include the relevent header or things aren't defined...
No, in the small test-programm i did not, since afaik <iomanip> just
defines/declares manipulators that take an argument.
Just to be sure it does not make any difference, i included <iomanip>
in the small test-programm. It did not fix the problem.
Darius.
"Darius.Moos AT esigma-systems DOT de" <pf*********@gmx.de> wrote in message news:<c6************@ID-193014.news.uni-berlin.de>... Hi,
there seems to be a problem with manipulators in g++/gcc-2.96. First
some are not defined in std:: and second, when using this manipulators
on streams, they give strange results. A small test-programm to show
it:
#include <cstdlib>
#include <iostream>
int main(int argc, char **argv)
{
//std::cout << std::fixed << std::showpoint << 0.123456789 << std::endl;
std::cout << std::ios::fixed << std::ios::showpoint << 0.123456789 << std::endl;
exit(EXIT_SUCCESS);
}
Compiling and running this programm gives the following result:
~$ ./a.out
40962560.123457
~$
Anyone got an idea whats going wrong here ?
Thanks in advance for your help.
Darius.
Well .. the manipulators are defined in <iomanip>; including that file
will put them in the std namespace as you were originally expecting.
What is happening in your code is that you are seeing the values of
std::ios::fixed and std::ios::showpoint on the stream. They are *not*
manipulators, or even functions, but rather implementation defined
flags for adding characteristics to the output stream. Try putting
spaces or tabs in between them to see which is which 8*).
As an aside, I think you should use "return EXIT_SUCCESS" at the end
of your program, rather than the call to exit.
HTH, Dave Moore
On Tue, 27 Apr 2004 14:52:22 +0200, "Darius.Moos AT esigma-systems DOT
de" <pf*********@gmx.de> wrote: On Tue, 27 Apr 2004 14:46:05 +0200, tom_usenet wrote: On Tue, 27 Apr 2004 14:14:19 +0200, "Darius.Moos AT esigma-systems DOT
de" <pf*********@gmx.de> wrote:On Tue, 27 Apr 2004 14:05:43 +0200, John Harrison wrote:
What happens when you try
std::cout << std::fixed << std::showpoint << 0.123456789 <<
std::endl;
Thinking about it that is the correct code.
They are not defined nor are they declared in std::, so the compiler
throws an appropriate error-message.
I could workaround the problem by (un)setting flags on the stream; just
wanted to use manipulators in the first place.
Have you included <iomanip> (or <iomanip.h> with older compilers)? You
have to include the relevent header or things aren't defined...
No, in the small test-programm i did not, since afaik <iomanip> just
defines/declares manipulators that take an argument.
Good point.
Just to be sure it does not make any difference, i included <iomanip>
in the small test-programm. It did not fix the problem.
Searching through the old GCC (2.96) headers, it looks like they just
didn't implement those manipulators (showpoint and fixed). Obvious
that version doesn't pretend to follow the C++ standard - the streams
aren't even templated.
The manipulators should be in the <ios> header IIRC - #including
<iostream> won't necessarily bring them in. endl and flush are in
<ostream>, and again, that should be explicitly included for the code
to be standard.
For old GCC you could implement the manipulators yourself...
Tom
--
C++ FAQ: http://www.parashift.com/c++-faq-lite/
C FAQ: http://www.eskimo.com/~scs/C-faq/top.html
In message <c6**********@korweta.task.gda.pl>, Jacek Dziedzic
<ja*************@janowo.net> writes Darius.Moos AT esigma-systems DOT de wrote:
Hi,
there seems to be a problem with manipulators in g++/gcc-2.96. First
some are not defined in std:: and second, when using this manipulators
on streams, they give strange results. A small test-programm to show
it:
Yes, I've seen it also. Somehow under g++-2.9x when you output
certain manipulators to the stream you get their internal
enum values sent to the stream instead of these manipulators
acting, how bizzare!
The fmtflags values are members of ios_base; the manipulator functions
are not.
The only two solutions I found were
a) upgrade to g++ 3.x, it's fixed in there
b) use cout.setf(...) instead -- it works fine.
HTH,
- J.
--
Richard Herring
In message <c6************@ID-193014.news.uni-berlin.de>, Darius.Moos AT
esigma-systems DOT de <pf*********@gmx.de> writes On Tue, 27 Apr 2004 14:46:05 +0200, tom_usenet wrote: On Tue, 27 Apr 2004 14:14:19 +0200, "Darius.Moos AT esigma-systems DOT
de" <pf*********@gmx.de> wrote:On Tue, 27 Apr 2004 14:05:43 +0200, John Harrison wrote:
What happens when you try
std::cout << std::fixed << std::showpoint << 0.123456789 <<
std::endl;
Thinking about it that is the correct code.
They are not defined nor are they declared in std::, so the compiler
throws an appropriate error-message.
I could workaround the problem by (un)setting flags on the stream; just
wanted to use manipulators in the first place.
Have you included <iomanip> (or <iomanip.h> with older compilers)? You
have to include the relevent header or things aren't defined...
No, in the small test-programm i did not, since afaik <iomanip> just
defines/declares manipulators that take an argument.
Just to be sure it does not make any difference, i included <iomanip>
in the small test-programm. It did not fix the problem.
You could try including <ios> which, according to 27.4, is where the
manipulator functions are supposed to be declared.
--
Richard Herring
On Tue, 27 Apr 2004 15:54:22 +0200, Dave Moore wrote: Well .. the manipulators are defined in <iomanip>; including that file
will put them in the std namespace as you were originally expecting.
~$ g++ ./test.cc
../test.cc: In function `int main (int, char **)':
../test.cc:10: `::fixed' undeclared (first use here)
../test.cc:10: `::showpoint' undeclared (first use here)
~$
What is happening in your code is that you are seeing the values of
std::ios::fixed and std::ios::showpoint on the stream. They are *not*
manipulators, or even functions, but rather implementation defined flags
for adding characteristics to the output stream. Try putting spaces or
tabs in between them to see which is which 8*).
Thanks for the clarification.
Darius.
On Tue, 27 Apr 2004 16:05:50 +0200, Richard Herring wrote:
[...] You could try including <ios> which, according to 27.4, is where the
manipulator functions are supposed to be declared.
~$ g++ ./test.cc
../test.cc:4:15: ios: No such file or directory
~$
On Tue, 27 Apr 2004 16:14:50 +0200, tom_usenet wrote:
[...] Searching through the old GCC (2.96) headers, it looks like they just
didn't implement those manipulators (showpoint and fixed). Obvious that
version doesn't pretend to follow the C++ standard - the streams aren't
even templated.
The manipulators should be in the <ios> header IIRC - #including
<iostream> won't necessarily bring them in. endl and flush are in
<ostream>, and again, that should be explicitly included for the code to
be standard.
~$ g++ ./test.cc
../test.cc:4:15: ios: No such file or directory
~$
For old GCC you could implement the manipulators yourself...
Yes, or use flags on the stream.
Darius.
In message <30**************************@posting.google.com >, Dave Moore
<dt*****@rijnh.nl> writes "Darius.Moos AT esigma-systems DOT de" <pf*********@gmx.de> wrote in
message news:<c6************@ID-193014.news.uni-berlin.de>... Hi,
there seems to be a problem with manipulators in g++/gcc-2.96. First
some are not defined in std:: and second, when using this manipulators
on streams, they give strange results. A small test-programm to show
it:
#include <cstdlib>
#include <iostream>
int main(int argc, char **argv)
{
//std::cout << std::fixed << std::showpoint << 0.123456789 <<
std::endl;
std::cout << std::ios::fixed << std::ios::showpoint <<
0.123456789 << std::endl;
exit(EXIT_SUCCESS);
}
Compiling and running this programm gives the following result:
~$ ./a.out
40962560.123457
~$
Anyone got an idea whats going wrong here ?
Thanks in advance for your help.
Darius.
Well .. the manipulators are defined in <iomanip>;
Only the ones that take arguments.
including that file
will put them in the std namespace as you were originally expecting.
What is happening in your code is that you are seeing the values of
std::ios::fixed and std::ios::showpoint on the stream. They are *not*
manipulators, or even functions, but rather implementation defined
flags for adding characteristics to the output stream. Try putting
spaces or tabs in between them to see which is which 8*).
As an aside, I think you should use "return EXIT_SUCCESS" at the end
of your program, rather than the call to exit.
HTH, Dave Moore
--
Richard Herring
"Darius.Moos AT esigma-systems DOT de" wrote:
there seems to be a problem with manipulators in g++/gcc-2.96.
This is an unstable development version of gcc.
If you can't go to gcc 3, at least see if you can go to gcc 2.95.2.
More info: http://gcc.gnu.org/gcc-2.96.html This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics
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