Just starting in C, and learning the basics.
I have created a simple program that when compiled, would expected to compile as a.out however gcc is compiling as a.exe.
GCC on Windows defaults to creating an file named a.exe on Windows, because the .exe extension is important - a file name a.out would not recognized as an executable program on Windows. The default output could be named a.out.exe but it would be different from a.out anyway, so it is just as sensible to produce a file named a.exe instead.
a.exe is less keypresses, too.
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Hello I have a project written in C that contains four .c files in different directories.These are ipv4_lib.c udp_lib.c projekt_C.c programLib.c
I 've written it in eclipse and everything works fine and it's easy to run,but now I have to run it in console.I have already run programs in console,but they were much easier and usually contained one or two headers in the same directory,so all I had to do was compile each files and run the main one.
But I have no idea how to run project.Is there some command to do that or something like that? Thanks
Look into GCC and Clang:
GCC: https://en.wikipedia.org/wiki/GNU_Compiler_Collection
Clang: https://en.wikipedia.org/wiki/Clang, https://clang.llvm.org/
Both are compilers you can use to compile your source code via the terminal. GCC is has been around longer and has better support but can be a little slow. Clang is newer, so less widely used, but is noticeably faster than GCC at compiling source code.
An example Clang command in your terminal:
clang -o hello hello.c && ./hello
This will compile your hello.c file and give you a hello executable that you can then run. We'll just assume that running the hello program prints Hello, World! to the console.
This question already has answers here:
Why do some compilers use "a.out" as the default name for executables?
(2 answers)
Closed 6 years ago.
I am learning C in Linux Mint, so I made a directory in which I place my programs. Whenever I compile a program, everytime a.out is being over-written with the new compiled program.
For ex. To compile a hello.c file I run command: cc hello.c, Now this program will create a.out, but I want it to be hello.out
Why is it?
How can I compile so that hello.c should create hello.out file?
Why only a.out is being created everytime when I make different programs in directory?
Because that's the default behavior of your compiler.
How can I compile so that hello.c should create hello.out file?
In general, refer to the documentation for the compiler you're using, which will tell you how to do this.
Assuming you're using gcc or similar, it's the -o option:
gcc hello.c -o hello.out
Default execution in Unix/Linux is a.out file. If you create your own executable then compile program like:
cc hello.c -o hello.out
./hello.out // manually created executable file
or
cc hello.c -o hello
./hello // manually created executable file
Unix/Linux doesn't care about extensions. -o hello basically your suggested name for the executable file that gcc would create.
Why every time a.out is created?
a.out remains the default output file name for executables created by certain compilers/linkers when no output name is specified, even though these executables are no longer in the a.out format.
Please see the wiki page of a.out.
Share your compilation command.
In the compilation command you can mention what the name of the output binary file, like: "gcc hello.c -o hello" then the binary file name will be (hello) because you mention after flag "-o" that you want to name the output file by the name "hello".
If you don't add the flag "-o" with a name, then the default name for the binary file is "a.out".
I have written a simple helloworld.c program. I can compile it and run it on linux terminal using gcc and ./a.out command. My query is regarding calling .o file without any extension. For example, to run my program instead of typing "./helloworld.out", I want to run it using keyword "helloworld" on my terminal. Any hints???
Thank You.
Just compile using
gcc -o helloworld helloworld.c
The -o option is for the output file name
Then use:
./helloworld
You need the ./ to tell the shell where the executable resides, since the current directory is unlikely to be in $PATH.
Recently, I found a program that is kind of a mix between an IDE and a text editor. It supports the syntax of the language and it does formatting, but it does not build and run the program for you. I am running Mac OS X 10.6.8. I looked up how to build C code using the Terminal application. The format is:
gcc [file]
Pretty simple. The problem is that I cannot change the directory of where the built file is outputted, nor can I change the name. By default, every file compiled is outputted in the home directory by the name of 'a.out.' How can I specify the output directory and name?
Thanks!
gcc has a -o option to change the output name. You can specify the path there. E.g.:
$ ls
program.c
$ gcc program.c -o program
$ ls
program program.c
$ mkdir bin
$ gcc program.c -o bin/program
$ ls bin
program
$
You should probably also want to know about a few other common options:
-std=c99, -std=gnu99: Use the c99 standard / with gnu extensions.
-Wall, -Wextra, -pedantic: Enable extra warnings.
-O0 -ggdb: Compile with debugging symbols. Look up how to use gdb.
-O2: Compile with processor-independent optimizations. Not compatible with -O0.
How can I execute a.exe using the Cygwin shell?
I created a C file in Eclipse on Windows and then used Cygwin to navigate to the directory. I called gcc on the C source file and a.exe was produced. I would like to run a.exe.
./a.exe at the prompt
you should just be able to call it by typing in the file name. You may have to call ./a.exe as the current directory is usually not on the path for security reasons.
just type ./a in the shell
To execute a file in the current directory, the syntax to use is: ./foo
As mentioned by allain, ./a.exe is the correct way to execute a.exe in the working directory using Cygwin.
Note: You may wish to use the -o parameter to cc to specify your own output filename. An example of this would be: cc helloworld.c -o helloworld.exe.
Thomas wrote:
Apparently, gcc doesn't behave like the one described in The C Programming language
It does in general. For your program to run on Windows it needs to end in .exe, "the C Programming language" was not written with Windows programmers in mind. As you've seen, cygwin emulates many, but not all, features of a POSIX environment.
gcc under cygwin does not generate a Linux executable output file of type " ELF 32-bit LSB executable," but it generates a windows executable of type "PE32 executable for MS Windows" which has a dependency on cygwin1.dll, so it needs to be run under cygwin shell. If u need to run it under dos prompt independently, they cygwin1.dll needs to be in your Windows PATH.
-AD.
Apparently, gcc doesn't behave like the one described in The C Programming language, where it says that the command cc helloworld.c produces a file called a.out which can be run by typing a.out on the prompt.
A Unix hasn't behaved in that way by default (so you can just write the executable name without ./ at the front) in a long time. It's called a.exe, because else Windows won't execute it, as it gets file types from the extension.
Just call it
> a
Make sure it will be found (path).
When you start in Cygwin you are in the "/home/Administrator" zone, so put your a.exe file there.
Then at the prompt run:
cd a.exe
It will be read in by Cygwin and you will be asked to install it.