Compilation of 'Hello World' gives likely wrong machine code

Learning
1

Im on Debian GNU/Linux 9 (stretch) 64-bit with OCaml version 4.05.0 and I want to compile the following file helloworld.ml into machine code using ocamlopt. To be more precise I have a .ml filethat which contains

print_string “Hello world!\n”;;

but is otherwise empty. I cd into, say …/folder than run

xx~$ ocamlopt …/folder/helloworld.ml

and I get a file helloworld.o … On debian I chmod this file to be executeable. I execute the file

xx~$ …/folder/helloworld.o

and I get the error massage:

bash: …/folder/hello_world.o: cannot execute binary file: Exec format error

I think this means that the machine code is for another machine. Maybe a 64bit/32bit mismatch. I don’t know. Am I doing something wrong?

Note: Since I needed the latest Ocaml version, which is not in the debian repository, I might have installed a 32bit version. Can I check that?

2

The .o file is not an executable file, it’s a C object file. You need to run the a.out file that was produced in the directory.

2 Likes
3

Oh… my mistake. Tanks

4

Since you did not specify the executable you want to be generated (option -o), the default a.out should be in the same directory.

Run it.

5

ocamlc -config | grep architecture maybe?

6

Check the current working directory of where you invoked the command (for that reason it may be better to use the -o to specify the name and location of the executable to produce).

1 Like
7

Problem solved. Thanks