when we compile a C program.. we get a .exe file which is use to execute the program. Then Is it true that this .exe file will run only on windows platform.??
Because I heard that .exe file contains MACHINE CODE. So I don't think platform should matter. But I also heard that C language is Platform Dependent.
Someone please Help me out.
You're correct, it is OS dependent.
BUT, C code can be re-compiled for any Operating System on the planet (and beyond!), and then be run on that system.
C code is platform independant, the generated executable is surely platform dependant. But i think i've heard of an OS that supported Windows executables, i don't remember which.
What do you mean by ".exe file?" A program file which is stored using PE file format? Or, more specifically, a Windows program? The .exe format itself isn't Windows-specific.
What else is it used for?
Well if it's Turbid-C, I suppose you could slide the floppy disks under a wobbly table leg or something.
You can also run Windows executables under Wine on Linux, but to run them on other platforms requires an emulator such a VirtualPC VirtualBox, VMWare...
.exe doesn't mean "Windows". DOS used .exe files also. Probably before your time, but the point remains.
Quzah.
Yes. It is a windows specific executable file. By itself it will not run anywhere else.Quote:
Originally Posted by Gaurav Singh
Similarly you're not going to run a linux or a mac program on windows.
Yes they all contain machine code, but that code makes calls into the Operating System and those calls are different on each OS... For example, the printf() function in the windows libraries is going to be totally unlike the printf() function in the Mac or Linux libraries.
The "C is multiplatform" is true only at the *source code* level and then, only because of standards like C99 that define a standard set of library functions for all platforms.
That said... there are programs called "Emulators" that can run Windows programs on other platforms... eg. Wine for Linux which lets you run some (but not all) windows programs under Linux. This is a program running your program, not your program running natively on another OS.
Although, the two things aren't really the same. A modern .exe file has a DOS exe header which points to a PE header -- it's the PE header that actually tells Windows what to do when it loads the executable. If such an exe is executed on DOS, which doesn't understand the PE format, it runs a little stub program that prints the message "This program cannot be run in DOS mode."Quote:
Originally Posted by quzah
Yes, every .exe file has a little DOS program built into its header just to print that error message. Ick
That is not precisely true. All executable files generally rely on some functionality provided by the host system (combination of hardware, operating system, etc). Some operating systems recognise particular executable formats.Quote:
Originally Posted by Gaurav Singh
The picture is blurred a little by emulators and virtual machines: for example, there are emulator environments that can be installed on unix systems that can support running executables targeted for windows systems.
That is only true in lands of fantasy.Quote:
Originally Posted by Gaurav Singh
Real software cannot run by itself - it requires some host system with physical properties (hardware) in order to run. Which means the hardware platform always matters, as does the software platform (eg operating system) that acts as an intermediary between applications and hardware.
In future, the nature of hardware and operating system platforms may change, but it will never be possible for software to just execute with no platform whatsoever.
That is not true. The C language itself is platform independent, because the C standard only specifies a minimum set of language and library features that can be implemented across all possible target systems.Quote:
Originally Posted by Gaurav Singh
The executable form that C code is translated to is platform dependent though. It is also possible to write C code that accesses platform-specific features (for example, C code that uses win32 API functions is specific to windows platforms).
Most C code is portable, which means it can be compiled on every operating system. The output machine code (the .exe file) is platform-dependent. If an executable file ends in ".exe", then it's most likely machine code for Windows or MS-DOS. Unix operating systems, like Linux, BSD, and OS X, can run Windows or MS-DOS binaries with Wine.
"In every Windows program, there's a little DOS program struggling to get out." :DQuote:
Originally Posted by brewbuck
An OS is just a "program running your program".Quote:
Originally Posted by CommonTater
Quzah.
Hehe, you asked for it! And who runs the OS?Quote:
Originally Posted by quzah