Date: Mon, 21 Apr 2003 12:33:35 +0200 From: Erik Trulsson <ertr1013@student.uu.se> To: Jason Griffis <jgriffis@ec.rr.com> Cc: freebsd-questions@freebsd.org Subject: Re: g++ question Message-ID: <20030421103334.GA92718@falcon.midgard.homeip.net> In-Reply-To: <200304210539.11227.jgriffis@ec.rr.com> References: <200304210539.11227.jgriffis@ec.rr.com>
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On Mon, Apr 21, 2003 at 05:39:11AM -0400, Jason Griffis wrote:
> I'm going through a C++ tutorial trying to increase my knowledge ;)
> Any way.. I wrote this little code:
>
> // My first program in C++
> #include <iostream>
>
> int main()
> {
> cout << "Hello World!";
> return 0;
> }
>
> When I compile it this way with g++ I get errors due to the compiler not
> finding the iostream file:
>
> $ g++ -o hello hello.cc
> hello.cc: In function `int main()':
> hello.cc:6: `cout' undeclared (first use this function)
> hello.cc:6: (Each undeclared identifier is reported only once for each
> function
> it appears in.)
> $
>
> I do have iostream in /usr/include so I don't see why it's doing this,
> whenever I change it to #include <iostream.h> it compiles fine but gives a
> warning of using a deprecated header file:
>
> $ g++ -o hello hello.cc
> In file included from /usr/include/g++/backward/iostream.h:31,
> from hello.cc:2:
> /usr/include/g++/backward/backward_warning.h:32:2: warning: #warning This file
> includes at least one deprecated or antiquated header. Please consider using
> one of the 32 headers found in section 17.4.1.2 of the C++ standard. Examples
> include substituting the <X> header for the <X.h> header for C++ includes, or
> <sstream> instead of the deprecated header <strstream.h>. To disable this
> warning use -Wno-deprecated.
> $
>
> Obviously it isn't that big of a deal with such a small program but when I
> move on to bigger projects that I'll want to use on different platforms other
> than FreeBSD these errors and warnings will be a major pain. Can anyone tell
> me what might be wrong with my system in order for g++ not to see the normal
> iostream header in /usr/include ?
[This is not really a FreeBSD question, but rather a C++ question.]
Nothing wrong with your system, but a problem with your program.
The tutorial you are using seems to be a bit old.
Although your program would have been just fine with older C++
implementations (except that they did not have headernames of the <foo>
style, only <foo.h>) , the newer, standard-compliant, implementations
have moved most of the standard library into the 'std' namespace.
The older <foo.h> name for the headers puts the functions into the
global namespace, but that is not recommended for new code.
Try using std::cout instead of just cout. (Or put a 'using namespace
std;' after the include.)
--
<Insert your favourite quote here.>
Erik Trulsson
ertr1013@student.uu.se
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