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hello guys... I am trying to write a simple library (in C++, for learning purpose) which is platform independent and can run on at least Windows and Linux (Ubuntu/Fedora).
Now I am using VS 2010. Can anyone guide me that how can I use this library on Linux and using which IDE?
Now if this approach has issues, can you guide that which IDE should I use (Eclipse may be?) on windows which will also work on Linux. Thanks for any pointers.
This world is going to explode due to international politics, SOON.
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Gday mate,
I used Eclipse years ago for developing Flex apps and was unimpressed. I picked it up again earlier this year when I played with android development but alas, again I was disappointed by the less than stellar performance. Damn you Java!
I'd be inclined to used Code::Blocks, it's compiled to native code, its available Win / Linux / Mac, 32 & 64 bit, will happily work with about a dozen or more compilers.
Also, without knowing the nature of the library it's impossible to know if this is a consideration or not, however - Code::Blocks has built-in support for using WxWidgets, which vastly eases the development of GUIs that are immediately portable.
It's also quite a small download - ~70MB for the IDE and GCC combined. Certainly worth a look imho.
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Writing a platform independent library is fairly easy - don't use any features of the OS' you're targeting and don't make any assumptions about data sizes, object layout and anything else that the standard says is undefined.
If you're happy developing on Windows then don't bother with an IDE for Linux. Do all your development on Windows, checking at least once a day that everything builds using gcc. When I do cross platform development I use VC++2010 and gcc from mingw to make sure it builds. I've yet to write code I intended to be portable that didn't run on Linux that compiled on gcc from mingw.
For controlling the build I'd suggest one of three things:
- If your library is really small stick the g++ command line in a shell script and run that. Really small is a couple of source files.
- If your library is a bit bigger then write a makefile. mingw comes with two versions of make, both of which have (for simple projects) the same behaviour on Linux. I'd use this for libraries up to about 20 source files that you only want to build and run on a couple of platforms
- If your library is effing huge (10s of source files) and you want it to build and run on just about every Unixy platform on the planet use GNU autotools[^]. This is a set of (rather complicated) but very flexible tools that by writing a couple of simple files lets you build, test and run your code on loads of different platforms. I've used them to run code code I wrote on VC++ for windows on Linux, FreeBSD (both 32 and 64 bit) and Solaris.
Whatever you use I'd suggest eventually looking at the autotools if you ever want to do any cross platform stuff. They're pretty ubiquitous in the GNU world - whenever you ./config a package on Linux you're using them.
Oh, one thing I forgot to mention up top... If you need stuff usually supplied by the OS have a dig around for a library that already does it. Three libraries I use a lot are boost [^](it's a test bed for new libraries that might be standardised one day and has sorts of useful stuff - I've used it for date/time, filesystem support, threads, interprocess comms, shared and unique pointers before were in the standard), OpenSSL [^](all your crypto needs admittedly with the most bent interface you've ever seen) and libcurl [^](everything for HTTP/FTP/GOPHER client development).
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Is there such a thing as a program that watches to make sure another program is running OK, and if it crashes, restarts it?
What is the preferred mechanism by which such a thing would be implemented?
(Not asking for code, just some ideas)
The difficult we do right away...
...the impossible takes slightly longer.
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This is usually done by having a Windows service that watches over your program.
There are several such programs available - Search for Application Watchdog[^]
Windows from Vista onward also supports Application Recovery and Restart[^] that you can use to have Windows restart your application in case of an unhandled exception.
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Thanks, Superman. 
The difficult we do right away...
...the impossible takes slightly longer.
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Developing whatch dog on windows is very easy, all you need to create a named mutex from the process (program) needed to moniter, and from your moniter process, wait for that mutex handle to be closed. If it get closed than restart your program.
If you are a Linux user than crontab is your friend, use crontab instead of develop new watchdog so that you can spent time to find out why you program is crashing.
On windows you can use cronw.
Good Luck.
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Hi,
Is anyone aware of a 'Task Manager Logging' App that can 'Capture and Record' most or all of the information viewable in Task Manager, sampled at regular intervals, in some form of Database. One of our clients experiences quite extensive memory leaks in Windows XP. We are confident that it is not our software, but it is a case of 'It only started happening after your stuff was installed' We would like to run something that takes a SnapShot, Starters say every fifteen minutes, and upon notifyable events, such as Process Starts or Stops.
Alternatively, is there a way to configure 'MS Windows Event Logging' to do the same.
I am just trying to figure out Why this customer gets 'Low virtual Memory' messages after two or three days running, and the system grinds to a Halt when that happens.
Regards,
Bram 
Bram van Kampen
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You could use Process Explorer[^].
Be sure to apply appropriate filters for logging because it does some extensive logging and could soon fill up your hard disk.
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Thanks
This seems to fit the bill.
Regards,
Bram van Kampen
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I am getting a syntax error on "namespace" declaring the following in MFC class variables. iostream is included in StdAfx header file.
namespace Test
{
int a;
int b;
}
Here is the partial error printout
error C2059: syntax error : 'namespace'
error C2334: unexpected token(s) preceding '{'; skipping apparent function body
Does that mean that in VC 6.0 I cannot use "namespace"?
Or did I missed something else?
Thanks for your time.
Vaclav
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Vaclav_Sal wrote: Does that mean that in VC 6.0 I cannot use "namespace"?
Probably.
Your code, exactly what you posted, compiles in VS 2005.
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you're missing something else. namespaces work fine in VC6.
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Addendum:
I build default MFC doc / view app and
I get same error with or without including either iostream or iostream.h.
To me that indictates that iostream does not define namespace.
Can it be defined somewhere else?
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what do you mean by "define namespace" ?
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If I get a syntax error the compiler does not recognize the "namespace" as valid syntax.
So it has to be defined to be vaild. Does not?
For example "if" is defined in similar way, but compiler flags "iff" as undeclared identifier.
I am just trying to find some reason why I am getting same syntax error with or without including iostream.
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'namespace' and 'if' are C++ keywords. they're not defined in headers anywhere, they're built into the compiler itself.
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You've probably left a semicolon, closing brace, closing parentheses or similar off the previous thing in the .h file.
Just out of interest, if you ever want to know if you can use a feature in a compiler just lop the code out and stick it in a .cpp file somewhere, making sure it's not dependent on any other code. In this case had you stuck:
namespace Test
{
int a;
int b;
}in a source file you'd have seen it compiles just fine in VC++6.0. As far as anything can be regarded as "compiling just fine" on that clunky piece of old rubbish.
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Hello Ash,
here is a snippet of VC 6.0 generated CView header file with my add and resulting compliler errors:
class CTESTView : public CView
{
protected: // create from serialization only
CTESTView();
DECLARE_DYNCREATE(CTESTView)
// Attributes
public:
CTESTDoc* GetDocument();
using namespace test
{
int a;
int b;
}
// Operations
public:
.........
This is how iostram is included in STdAfx.h file:
#if !defined(AFX_STDAFX_H__D78D5AFB_F290_4B69_9F5A_23EC3FA245D9__INCLUDED_)
#define AFX_STDAFX_H__D78D5AFB_F290_4B69_9F5A_23EC3FA245D9__INCLUDED_
#if _MSC_VER > 1000
#pragma once
#endif // _MSC_VER > 1000
#include <iostream> <b>silly but the CodeProject edit box did not copy stuff in "arrow brackets" - but it is here - iostream
It did not show up in preview, go figure.
</b>
#define VC_EXTRALEAN // Exclude rarely-used stuff from Windows headers
.....
And here is the full compiler output regardless of inclusion of iostream or not:
--------------------Configuration: TEST - Win32 Debug--------------------
Compiling...
TEST.cpp
z:\0\0 mdi\test\bamesapce\test\testview.h(23) : error C2059: syntax error : 'namespace'
z:\0\0 mdi\test\bamesapce\test\testview.h(24) : error C2334: unexpected token(s) preceding '{'; skipping apparent function body
TESTView.cpp
z:\0\0 mdi\test\bamesapce\test\testview.h(23) : error C2059: syntax error : 'namespace'
z:\0\0 mdi\test\bamesapce\test\testview.h(24) : error C2334: unexpected token(s) preceding '{'; skipping apparent function body
Generating Code...
Error executing cl.exe.
TEST.exe - 4 error(s), 0 warning(s)
I am ready to stop trying this, I really do not need it, but the stuff I am modyfying is using it. After succes of using
pure virtual class / function ( BTW many thanks for all you input on that ) I am just "looking for punishment".
Is it possible that I have some kinda of conflict with std namespace?
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using namespace test
{
int a;
int b;
}
that's the problem.
it should be:
namespace test
{
int a;
int b;
};
and then, in your .cpp:
using namespace test; <--- fixed
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Thanks Chris,
and this is the compiler output after your suggestion:
TEST.cpp
z:\0\0 mdi\test\bamesapce\test\testview.h(23) : error C2059: syntax error : 'namespace'
z:\0\0 mdi\test\bamesapce\test\testview.h(24) : error C2334: unexpected token(s) preceding '{'; skipping apparent function body
TESTDoc.cpp
TESTView.cpp
z:\0\0 mdi\test\bamesapce\test\testview.h(23) : error C2059: syntax error : 'namespace'
z:\0\0 mdi\test\bamesapce\test\testview.h(24) : error C2334: unexpected token(s) preceding '{'; skipping apparent function body
Z:\0\0 MDI\TEST\BAMESAPCE\TEST\TESTView.cpp(60) : error C2873: 'test' : symbol cannot be used in a using-declaration
Generating Code...
Error executing cl.exe.
TEST.exe - 5 error(s), 0 warning(s)
And here is what my ancient MSDN say about namespace:
namespace Declaration
C++ Specific —>
namespace [identifier] { namespace-body }
A namespace declaration identifies and assigns a name to a declarative region.
The identifier in a namespace declaration must be unique in the declarative region in which it is used. The identifier is the name of the namespace and is used to reference its members.
The declarative region of a namespace declaration is its namespace-body.
END C++ Specific
Notice - no semicolon.
And if it is a keyword it must not be in my VC6.0 Sp6 stuff.
I give up.
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here is the complete source of a test program demonstrating the use of namespaces in VC6:
namespace foo
{
class testing
{
public:
testing()
{
i = 10;
}
int i;
};
};
using namespace foo;
int main(int argc, char* argv[])
{
testing t();
return 0;
}
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Hi Chris - your line:
testing t(); doesn't actually create a new object. It's a prototype for a function that takes no parameters and returns a testing object.
It's a real bugger with C++ and bites loads of people. It's also the reason that the latest C++ standard introduced uniform initialisation (using braces where we've used parenthesis up to now).
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ok. but that's not the point here.
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