conio.h is missing from Windows - c

I usually use VS but trying cygwin for the first time. I am using windows 7 but on compiling hello world program using gcc, it says "fatal error: conio.h: no such file or directory".
I am using Windows 7 and it seems conio.h is missing from my system. Can someone please tell me how to resolve this issue.
Thanks!!

In Cygwin there doesn't exist any such header file called conio.h! Also, you don't need it either because it automatically holds screen for you without using getch() and for clrscr() you do have system("clear") in Cygwin!

conio not being part of the standard library, you cannot expect it to be available cross-platform, or even between compilers on the same platform.
Being, non-standard, the name conio has been used by both Borland and Microsoft for libraries with differing APIs - Microsoft's is much smaller. So for that reason you might avoid it for portability.
It is not a matter of conio not being on Windows, Cygwin is a POSIX API layer and tool-chain for building and running POSIX code on Windows. The libraries provided with it are independent of those provided with Visual Studio.
There are a number of solutions including:
Use an alternative console I/O library, such as ncurses.
Use a conio source code implementation for Linux such as this (which uses ncurses and implements Borland's API).
The second solution is perhaps useful if you have a lot of legacy code using conio, but is overkill if you just want to prevent a console windows from closing. For that you could just use getchar() in any case and accept that you will have to press enter rather than any key.
If you are using Cygwin just to be able to use GCC on Windows, you might be better off using MinGW/GCC instead. This uses Microsoft's C runtime rather than GNU, and the Win32 API rather than POSIX.

Related

Clearing screen and kbhit() function

I got some problems writing my snake game program. I need to make game working on linux and windows. I found some topics how to clear screen on linux and windows using the #ifdef Windows etc. The problem is i need to use C89 standard, and im not sure that system("cls") is in C89. Could you help me with finding C89 functions to clear screen, and tell me something about kbhit() function on linux? Sorry for my english, and thanks for help.
C89 does not have terminal handling functions. Instead, you should use OS specific functions. So you need to have, say, a source file only for windows functions and another for linux. Another option is to use a cross platform library. I would choose ncurses for this task:
http://www.tldp.org/HOWTO/NCURSES-Programming-HOWTO/
It works on any unix system, including linux and Mac OS. For windows versions, see:
Is ncurses available for windows?
With ncurses, you have functions like erase() and clear() to clear the screen.
On Unix-liked systems including Linux and macOS, you can use ncurses library (POSIX API). In case of Windows (or even Linux or macOS), the following code will work on ANSI terminals on any systems.
printf("\033[2J\033[H");
/* or */
printf("\033[0;0f");

A simple explanation of what is MinGW

I'm an avid Python user and it seems that I require MinGW to be installed on my Windows machine to compile some libraries. I'm a little confused about MinGW and GCC. Here's my question (from a real dummy point of view):
So Python is language which both interpreted and compiled. There are Linux and Windows implementations of Python which one simply installs and used the binary to a execute his code. They come bundled with a bunch of built-in libraries that you can use. It's the same with Ruby from what I've read.
Now, I've done a tiny bit a of C and I know that one has a to compile it. It has its built-in libraries which seem to be called header files which you can use. Now, back in the school day's, C, was writing code in a vi-like IDE called Turbo-C and then hitting F9 to compile it. That's pretty much where my C education ends.
What is MinGW and what is GCC? I've been mainly working on Windows systems and have even recently begun using Cygwin. Aren't they the same?
A simple explanation hitting these areas would be helpful.
(My apologies if this post sounds silly/stupid. I thought I'd ask here. Ignoring these core bits never made anyone a better programmer.)
Thanks everyone.
MinGW is a complete GCC toolchain (including half a dozen frontends, such as C, C++, Ada, Go, and whatnot) for the Windows platform which compiles for and links to the Windows OS component C Runtime Library in msvcrt.dll. Rather it tries to be minimal (hence the name).
This means, unlike Cygwin, MinGW does not attempt to offer a complete POSIX layer on top of Windows, but on the other hand it does not require you to link with a special compatibility library.
It therefore also does not have any GPL-license implications for the programs you write (notable exception: profiling libraries, but you will not normally distribute those so that does not matter).
The newer MinGW-w64 comes with a roughly 99% complete Windows API binding (excluding ATL and such) including x64 support and experimental ARM implementations. You may occasionally find some exotic constant undefined, but for what 99% of the people use 99% of the time, it just works perfectly well.
You can also use the bigger part of what's in POSIX, as long as it is implemented in some form under Windows. The one major POSIX thing that does not work with MinGW is fork, simply because there is no such thing under Windows (Cygwin goes through a lot of pain to implement it).
There are a few other minor things, but all in all, most things kind of work anyway.
So, in a very very simplified sentence: MinGW(-w64) is a "no-frills compiler thingie" that lets you write native binary executables for Windows, not only in C and C++, but also other languages.
To compile C program you need a C implementation for your specific computer.
C implementations consist, basically, of a compiler (its preprocesser and headers) and a library (the ready-made executable code).
On a computer with Windows installed, the library that contains most ready-made executable code is not compatible with gcc compiler ... so to use this compiler in Windows you need a different library: that's where MinGW enters. MinGW provides, among other things, the library(ies) needed for making a C implementation together with gcc.
The Windows library and MSVC together make a different implementation.
MinGW is a suite of development tools that contains GCC (among others), and GCC is a C compiler within that suite.
MinGW is an implementation of most of the GNU building utilities, like gcc and make on windows, while gcc is only the compiler. Cygwin is a lot bigger and sophisticated package, wich installs a lot more than MinGW.
The only reason for existence of MinGW is to provide linux-like environment for developers not capable of using native windows tools. It is inferior in almost every respect to Microsoft tooolchains on Win32/Win64 platforms, BUT it provides environment where linux developer does not have to learn anything new AND he/she can compile linux code almost without modifications. It is a questionable approach , but many people find that convenience more important than other aspects of the development .
It has nothing to do with C or C++ as was indicated in earlier answers, it has everything to do with the environment developer wants. Argument about GNU toolchains on windows and its nessessety, is just that - an argument
GCC - unix/linux compiler,
MinGW - approximation of GCC on Windows environment,
Microsoft compiler and Intel compiler - more of the same as names suggest(both produce much , much better programs on Windows then MinGW, btw)

Getting Free RAM in Windows Programmatically?

All,
Need some help here. I am from a purely Java background and don't know much about C programming. Basically I need to write a C program (and create an executable) which would output the number of Free Bytes (RAM) on a Windows machine (XP/2008/7)
I have doing some research about it and found that there is a function called GlobalMemoryStatusEx and also a link on this:
http://msdn.microsoft.com/en-us/library/aa366589(v=vs.85).aspx
I have installed cygwin with gcc and the above program doesn't even compile for me. I know I am doing something stupid here..
$ gcc hello.c -o hello.exe
hello.c:3:19: error: tchar.h: No such file or directory
hello.c: In function `main':
hello.c:7: error: `MEMORYSTATUSEX' undeclared (first use in this function)
hello.c:7: error: (Each undeclared identifier is reported only once
hello.c:7: error: for each function it appears in.)
hello.c:7: error: expected `;' before `statex'
hello.c:9: error: `statex' undeclared (first use in this function)
Any help is very much appreciated!
As larsmans said, cygwin is not a Windows native compiler. In addition to MinGW, you might also consider Visual C++ 2010 Express.
Cygwin by default emulates a Unix API on Windows, rather than presenting the Windows API.
You may have more success with the MinGW package, which is GCC for Windows + Windows API.
If you are unfamiliar with C, and all you want to do is write this little program for Windows, you might find it easier to get started with the free Visual C++ Express. Chances are that MSDN examples will work out of the box.
Edit: You mention Java, but it is not totally clear whether the sole purpose of this C app is to be invoked from Java. In case it is, I thought I'd mention something called JNative. It appears to be a pure Java library that contains, among other things, a wrapper for GlobalMemoryStatusEx. Note that I found JNative via a Google search and haven't used it myself.
The function to which you refer is a Windows API function, which means you cannot call that function from cygwin, which is a POSIX emulation layer on top of Windows.
You have a few options at this point:
You could download download and install the Windows SDK, which includes the Visual Studio C/C++ compiler(s), for free.
You could download a copy of Visual C++ Express Edition for free.
If you are a student, you could get a full copy of Visual Studio 2010 from MSDNAA (provided by your University) or from DreamSpark.
You could purchase a full copy of Visual Studio.
You could download and install MinGW, which is the GCC compilers ported to Windows.
Note that all of the Microsoft compilers support the entire Win32 API. MinGW is limited in its handling of Unicode on Windows, it does not support COM (so if you want to call COM APIs it's a pain), and it doesn't include all of the headers included with the Windows SDK.
GCC is a great compiler, its just not all that great in terms of its Windows support.
The answers presented are correct, but I don't feel that they explain the problem properly.
Unix and Unix-like operating systems strive to conform to a standard API called POSIX. Windpws does not conform to POSIX. Cygwin was written as way to provide POSIX compliance on Windows. Thus, when you compile on Cygwin, you are compiling on a POSIX API, not a Windows API. The function you found on MSDN does not exist in POSIX. Threefore, you get compile errors.
MinGW is gcc ported to Windows. It is aware of Windows API's with the proper includes. Visual Studio's nmake is the same in this regard (provides access to the Win API).
To use cygwin gcc to compile programs using the Win32 API, you'll want the mingw-i686-headers package (which includes header files like tchar.h).
Then, you may also need to define some macros to enable newer APIs.

what software should i use when i want to study c

i want to write code use notepad and compile the c code use cmd on windows (like java),
what software should i use ,
gcc for windows
cygwin
Turbo C
gvim
thanks
An excellent option for Windows is the Visual C++ Express Edition (which is free). This is a full IDE, compiler, and debugger and is a great way to get started.
GCC is also a good option if for some reason you wish to avoid an IDE. I wouldn't recommend this for a beginner, though.
Please don't use Turbo C, it's very old and you will have problems with it.
Cygwin is a popular linux environment for Windows.
Gvim is an editor and (in my opinion) has a very high learning curve. You could use Notepad++ or Code::Blocks to develop your code in.
mingw is also a good option to start with.
IMO you should avoid IDEs: a beginner needs to actually see and feel the whole process of compiling by invoking the compiler from a terminal, not by simply pressing some keys and bang! Also most of the IDEs have code completion facilities which is not good for beginners (especially for C). So I would go with vim (or gvim) and cygwin.
PS: Give Linux a try, you might actually like it; then vim and gcc.
Use cygwin. It's just about the only way to get a C environment on Windows that's both modern (i.e. not 16-bit, DOS-based) and conformant to the standards, and with it you get a fairly-complete POSIX environment, which allows you to actually do interesting things with C.
The classics would be Cygwin and MSYS/MinGW.
Cygwin provides a Linux API compatibility layer and includes a package manager which provides access to many well-known Linux applications (ie batteries included).
MSYS/MinGW only provides a minimal userland to get the GNU build system working.
Both come with their own shell environment, but can be used from Windows' command line as well.
Binaries created with Cygwin-gcc won't work without cygwin1.dll, but you get all the benefits of a mostly-POSIX environment. You can also use Cygwin's MinGW package for cross-compilation and thus create stand-alone binaries.
Other solutions are possible: Currently, I'm using the MinGW compiler together with the Cygwin userland from the Windows command line...
I think cygwin itself named as gcc for windows.
also gvim is not a compiler , It is a very nice and powerful tool for code editing.Also you can try emacs and kwrite
Some suggestions from my side:
In windows, you need to install a third party software to try all programming stuffs(c,c++ etc) ,Most of the times it is having GUI implementations and you didn't get any exact idea behind the code execution flow.also the command prompt of windows not at all efficient as linux shell.
But if you install a good linux distro (ubuntu/fedora/cent os/debian/pardus/suse/arch linux),all default compilers,debuggers and editors are installed within the OS and you can try the basic and all advanced programs by just opening the terminal(shell).Also the shell is a more powerful tool and you can enjoy all kind of automation comamnds(I mean scripting).
Also: for your added information, most of the embedded programmers in the industry prefer command line execution unlike GUI implementation because it is too fast than GUI.

C: Running Unix configure file in Windows

I would like to port a few applications that I use on Linux to Windows. In particular I have been working on wdiff. A program that compares the differences word by word of two files.
Currently I have been able to successfully compile the program on windows through Cygwin. However, I would like to run the program natively on Windows similar to the Project: UnixUtils.
How would I go about porting unix utilities on a windows environment?
My possible guess it to manually create the ./configure file so that I can create a proper makefile. Am I on the right track? Has anyone had experience porting GNU software to windows?
Update:
I've compiled it on Code::Blocks and I get two errors:
wdiff.c|226|error: `SIGPIPE'
undeclared (first use in this
function)
readpipe.c:71: undefined reference to `_pipe'
readpipe.c:74: undefined reference to `_fork
This is a linux signal that is not supported by windows... equvilancy?
wdiff.c|1198|error: `PRODUCT'
undeclared (first use in this
function)|
this is in the configure.in file... hardcode would probably be the fastest solution...
Outcome:
MSYS took care of the configure problems, however MinGW couldnt solve the posix issues. I attempt to utilize pthreads as recommended by mrjoltcola. However, after several hours I couldnt get it to compile nor link using the provided libraries. I think if this had worked it would have been the solution I was after.
Special mention to Michael Madsen for MSYS.
Yes. If you stick to the standard C library, and POSIX functions, most is available on Windows. You may just have to find the implementations. There are implementations of things that do not require Cywgin or MinGW (such as a pthreads package, etc.)
Also, there is a great book that is written in the style of W. Richard Steven's Advanced Proramming in the UNIX Environment, and the book is Windows System Programming, author Johnson Hart. He has a 4th edition. It focuses on System Programming, there is no GUI treatment whatsoever.
http://www.amazon.com/Windows-Programming-Addison-Wesley-Microsoft-Technology/dp/0321657748
It is the best book I know of for a UNIX programming moving to Windows.
You can have a look at MinGW (and MSYS), which are similar to cygwin, but gcc produce native Windows executables. However, since the Unix emulation is not as good as cygwin, you may have to adjust your code.
Always try to following standarts even when porting applications. POSIX compliant compilers exist on windows/Linux. You can try mingw. It has full toolchain required to build standart POSIX application (GNU Linux as well). Check out Dev-Cpp it eases the work.
MinGW is about the easiest way to get gcc and associated binary utilities (including gdb) on a Windows PC. It includes header files and import libraries so that you can call native Windows APIs. If you want more of an integrated IDE development environment you could download Microsoft's free Visual Studio Express C++.
Either way you'll likely have to convert some of the function calls to use Windows specific APIs (if you want a book I'd also recommend the Hart book mentioned in mrjoltcola's answer). For simple command line tools this conversion is usually not a huge deal, the big porting nightmares tend to involve tools with GUIs which have deep embedded dependencies on the GUI framework provided by the OS.

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