I'm new to Linux and C and when trying to run a basic "Hello World" script, i kept getting the same two errors. I have confirmed that everything in the program is correct.
errors gotten when trying to compile code
You are running the gcc command from the home directory (~) when the hello.c file is in ~/Documents.
Either navigate to Documents using cd before running gcc or place hello.c in the home directory.
Go to the folder at which your file is existing, and then save the program.
foldername>~$ gcc filename.c
I would like to know how I can prevent gcc under Cygwin from automatically adding the .exe extension to compiled files, because I just caused myself a lot of confusion with "missing files". For context, I am working on a C project for university and I usually work in the labs which run Ubuntu (dual-boot with Windows), but to work from home I prefer using my Windows machine, ergo Cygwin. If I just remove the extension it still works just fine on either system, but it is rather frustrating to have to change the command to include the extension whenever I've just compiled it under Cygwin.
I looked up the FAQ from Cygwin to find that it is probably an issue related to an environment variable in .bashrc or .bash_profile (see here), but I am no command-line ninja and am not very familiar with editing configuration files... I found two related questions as well that show the same behaviour, but have nothing to do with trying to change it:
Compiling with gcc (cygwin on windows)
Executable file generated using gcc under cygwin
Any ideas?
It is actually for an MPI in C project so I have a Makefile that calls mpicc but that is not really relevant to the problem, since I just tried with gcc as well and both do the same thing. For the purpose of this question, the commands and outputs I get are:
$ gcc -o hello hello.c
$ ls
hello.c hello.exe
$./hello
Hello, world!
$./hello.exe
Hello, world!
Note that running with or without the extension does the same thing in the shell, but it does not with mpirun which is why I want to change this behaviour.
I eventually decided that Windows is not the programming environment for me. From now on all work that can be done in Linux will be.
7 years and no one to tell ?
My answer : Yes it's possible to produce an executable without .exe extension under Cygwin GCC. By telling the linker how to name its output.
$ echo -e "#include <stdio.h>\nint main(int nbargs, char *args[]) {
printf(\"Hello \\\n\");
}" | gcc -pipe -x c - -Wl,-oess2
This will produce an ess PE32 / PE32+ executable file, not a ess.exe.
The -pipe option instructs the GCC build chain to not write temporary files but use pipe between stages instead. The -Wl,-o option inhibits the default --force-exe-suffix.
And this way you can really nullify Cygwin GCC output with -Wl,-o/dev/null, the linker will fail when trying to close the output but you can trap the error message. If you get it, you can be assured that GCC reaches the link stage far enough to produce an output, which means that GCC can build an executable with this code.
From the ld man page :
--noinhibit-exec Retain the executable output file whenever it is still usable. Normally, the linker will not produce an output file if
it encounters errors during the link process; it exits without writing
an output file when it issues any error whatsoever.
DO NOT USE -Wl,-o/dev/stdout under Cygwin. Under Cygwin, /dev/stdout is a symlink, and if the linker fails it will DELETE /dev/stdout.
On the other end, -Wl,-o/proc/self/fd/1 will do no harm, but the linker will fail and will produce only an error message on stdout. Currently, it seems there is no direct way under Cygwin to pipe the linker output, even with named pipes.
The automatic exe extension for executables is there for a reason (Windows requires it). You should deconfuse (aka educate :-) yourself and accept the way Cygwin works. This is a feature rooted so deeply in the Cygwin/Windows guts that it is almost impossible to make it run without it.
For a "Unix feeling on Windows" with a different approach you want to check out AT&T's UWin.
I am trying to run a MPI program with C language.
I have installed GCC compiler and the openmpi libraries. I am running ubuntu Linux and Netbeans IDE. My challenge is that after including ‘mpi.h’ in my header file and compiling the application, I still get ‘fatal error : cannot find file mpi.c’. I have the files in home/user/lib/openmpi/include, but I cant get it too work.
Can anyone help?
You could try to change the compiler to /path/mpicc and the debugger to mpirun. This should work, although I did not test it, but probably the best way to compile MPI code is via terminal.
If you really depend on the IDE you cound try writing your code with it (to take advantage of auto-completion and such) and compile it in terminal using mpicc -o main.exe main.cpp [other .cpp files] and run it with mpirun -np number_of_processes_to_use ./main.exe [args]. You could write a small script or a Makefile to do it all in one command.
Good luck!
to save yourself some sanity, I'd recommend opening up a terminal and going from there (at least until you figure out what's what).
Also, using the mpi compiler to do things would simplify your life. (and likely automatically solve the missing source issue, as it should know where they are by default).
If you still can't locate them during compile then I'd look at adding the location where mpi.c & mpi.h are located to your C Include Path: How to add a default include path for gcc in linux?
C:\slite\1.1>gcc -c ".\src\SDR.c" -o ".\obj\SDR.o" -I".\inc"
C:\slite\1.1>gcc ".\obj\SDR.o" -o ".\exe\SDR.exe" -L".\lib" -lsres -lshis
.\lib/sres.dll: file not recognized: File format not recognized
collect2: ld returned 1 exit status
Could not compile C program using gcc after installing cygwin in Windows 2003.
Before installing cygwin, I was able to compile successfully.
I am compiling the code from Command prompt, not from cygwin terminal.
The gcc being used is from Dev-Cpp distribution.
Is the problem because of the directory separator ('/') between the libraries directory specified by -L and individual libs specified by -l, being used by gcc after cygwin was installed?
If i try to compile in cygwin terminal I am getting unknown function calls error, though the functions are defined in the headers included.
EDIT:
C:\srmlite\x7.5.0.146-1600>where gcc
C:\Dev-Cpp\bin\gcc.exe
The gcc was not from cygwin.
I have uninstalled cygwin and removed its directory too. I still see this problem.
Try to add the correct bin directory into the path in your Environment variables.
Something like this: C:\soft\cygwin\bin
Seems that Cygwin modified the default environment, adding itself to %PATH%, so you're actually calling cygwin's gcc, check that out.
I'm enrolled in a masters computer science course. The course is using C and the instructor wants us to use Cygwin to compile programs if we are using windows.
I've downloaded and installed Cygwin and I've ensured that I've installed the GCC compiler.
But I don't know where to go from here. I need to compile a single source file that has a basic include.
#include <stdio.h>
Lets assume the file is on my desktop (it is not, but for the sake of argument). How do I navigate to the desktop from the bash shell? I assume once I've navigated to the correct location in bash, I simply execute:
gcc myProgram.c -o myProgram
Update: Following different instructions posted below, I was able to compile the program; I thank you for that. But when I execute the resulting binary I get the following. How can I compile or execute this program so I don't get the error? Again, thank you.
This application has failed to start because cygwin1.dll was not found. Re-installing the application may fix this problem.
when you start in cygwin, you are in your $HOME, like in unix generally, which maps to c:/cygwin/home/$YOURNAME by default. So you could put everything there.
You can also access the c: drive from cygwin through /cygdrive/c/ (e.g. /cygdrive/c/Documents anb Settings/yourname/Desktop).
Regarding your updated question about the missing cygwin1.dll.
From the Cygwin terminal check,
ls /usr/bin/cygwin1.dll
If it is not present (I doubt that), your installation is not properly done.
Then, check your path with,
echo $PATH
This will give : separated list of paths. It MUST contain /usr/bin. If you find that missing add it with,
export PATH=/usr/bin:$PATH
Finally,
I hope you are using Cygwin from the cygwin terminal (the little green+black icon installed with Cygwin), or MinTTY (if you installed that).
And, you have not moved the compiled EXE to a different machine which does not have Cygwin installed (if you do that, you will need to carry the cygwin1.dll to that machine -- keep it in the same folder as the compiled EXE).
Just to summarize, here are some commands that navigate to a directory and compile code using Cygwin and Windows Vista:
Start a Cygwin shell.
At the prompt, use cd to change to the appropriate directory:
$ cd /cygdrive/c/Users/nate/Desktop
Use ls to list the files in the directory:
$ ls
prog.c
Use the gcc command to compile a file in this directory:
$ gcc prog.c -o prog
If you don't see any errors, you should be able to run the resulting program:
$ ./prog
Update:
For the "Cygwin1.dll not found" error, I like Nik's answer. You might also check out this related post about cygwin1.dll not found, which suggests adding c:\cygwin\bin\ to your Windows PATH.
There are instructions on how to change the Windows PATH variable for Windows XP, and on Vista I think it's similar.
Go to Control Panel -> System
Select Advanced System Settings
Click on the Advanced tab
Click on Environment Variables
Under System Variables, find the Path entry and click Edit
Add c:\cygwin\bin to the list, making sure to separate it from any previous items with a semicolon
Look for (that is, cd to)
/cygdrive/c/
that will usually be your C:\
Also look at Using Cygwin, the Lifehacker introduction (June/2006) and, this biomed page at PhysioNet.
Regarding the cygwin1.dll not found error, a solution I have used for at least 8 years is to add the Cygwin bin directories to the end of my %PATH% in My Computer -> Properties -> Advanced -> Environment Variables. I add them to the end of the path so in my normal work, they are searched last, minimizing the possibility of conflicts (in fact, I have had no problems with conflicts in all this time).
When you invoke the Cygwin Bash Shell, those directories get prepended to the %PATH% so everything works as intended in that environment as well.
When not running in Cygwin shell, my %PATH% is:
Path=c:\opt\perl\bin; \
...
C:\opt\cygwin\bin; \
C:\opt\cygwin\usr\bin; \
C:\opt\cygwin\usr\local\bin;
This way, for example, ActiveState Perl's perl is found first when I am not in a Cygwin Shell, but the Cygwin perl is found when I am working in the Cygwin Shell.
If you are not comfortable with bash, you can continue to work in a standard windows command (i.e. DOS) shell.
For this to work you must add C:\cygwin\bin (or your local alternative) to the Windows PATH variable.
With this done, you may:
1) Open a command (DOS) shell
2) Change the directory to the location of your code (c:, then cd path\to\file)
3) gcc myProgram.c -o myProgram
As mentioned in nik's response, the "Using Cygwin" documentation is a great place to learn more.
If you just do gcc program.c -o program -mno-cygwin it will compile just fine and you won't need to add cygwin1.dll to your path and you can just go ahead and distribute your executable to a computer which doesn't have cygwin installed and it will still run. Hope this helps
Windows path C:\src under cygwin becomes /cygdrive/c/src
Compiling your C program using Cygwin
We will be using the gcc compiler on Cygwin to compile programs.
1) Launch Cygwin
2) Change to the directory you created for this class by typing
cd c:/windows/desktop
3) Compile the program by typing
gcc myProgram.c -o myProgram
the command gcc invokes the gcc compiler to compile your C program.
You might be better off editing a file inside of cygwin shell. Normally it has default user directory when you start it up. You can edit a file from the shell doing something like "vi somefile.c" or "emacs somefile.c". That's assuming vi or emacs are installed in cygwin.
If you want to file on your desktop, you'll have to go to a path similar (on XP) to "/cygwindrive/c/Documents\ and\ Settings/Frank/Desktop" (If memory serves correctly). Just cd to that path, and run your command on the file.
Cygwin is very cool! You can compile programs from other systems (Linux, for example), and they will work. I'm talking communications programs, or web servers, even.
Here is one trick. If you are looking at your file in the Windows File Explorer, you can type "cd " in your bash windows, then drag from explorer's address bar into the cygwin window, and the full path will be copied! This works in the Windows command shell as well, by the way.
Also: While "cd /cygdrive/c" is the formal path, it will also accept "cd c:" as a shortcut. You may need to do this before you drag in the rest of the path.
The stdio.h file should be found automatically, as it would be on a conventional system.
This file (cygwin1.dll) is cygwin dependency similar to qt dependency.you must copy this file and similar files that appear in such messages error, from "cygwin/bin" to folder of the your program .Also this is necessary to run in another computer that have NOT cygwin!