Cygwin g++ does not allow ./file on windows 8

Question

When I compiled a program on cygwin like the following

g++ -o helloworld helloworld.cpp

An executable helloworld.exe is created. However, I could not execute the program by using

./helloworld

but instead I need to use

./helloworld.exe

Is there a way to enable the cygwin to recognize helloworld as an executable for the file helloworld.exe

Answer 1

This isn't directly related to g++.

Windows requires executable files (of the kind generated by a compiler, not batch files) to have names with a .exe extension; that's how the OS recognizes them as executables.

Cygwin, as you know, implements a POSIX-like layer on top of Windows. POSIX systems (UNIX, Linux, et al) do not require any special suffix for executable files; the OS recognizes a file as executable based on a "magic number" in the file itself and the executable bit in its directory entry.

To bridge this gap, Cygwin treats the .exe extension separately. Compilers like g++ generate executable files with the .exe suffix, but Cygwin lets you execute a file named helloworld.exe by typing either ./helloworld.exe or ./helloworld. (This even applies to other operations; ls -l helloworld will show you information about helloworld.exe -- assuming there's not also a file named just helloworld.)

In this case, based in information you've provided in the comments, you apparently have two executable files in your current directory, helloworld.exe and helloworld.

I'm not 100% sure what Cygwin will do in this case, but the solution is to delete the helloworld file and make sure that your executables have the required .exe extension. Cygwin compilers will do this for you by default; even if you run

g++ helloworld.cpp -o helloworld

it will generate an executable file named helloworld.exe.

I don't know what you did to create an executable file without the .exe extension. Whatever it was, don't do it again.