Why a Program Runs on Linux but Fails on Windows: Compilation, Linking, and ELF Explained

Background

Even though a program ultimately becomes machine code, the same binary may run on Linux but not on Windows, and vice‑versa, because the executable formats and loading mechanisms differ.

Compilation, Assembly, and Linking

A C source file is first compiled into assembly, then assembled into object files containing machine code. These object files ( add_lib.o and link_example.o) are not executable by themselves; they lack the necessary address resolution.

Using gcc -c add_lib.c and gcc -c link_example.c produces the object files, and objdump -d -M intel -S link_example.o can display their disassembly.

Attempting to run an object file directly (e.g., ./link_example.o) results in a “Permission denied” or “cannot execute binary file: Exec format error” because the file lacks an executable header and proper address mapping.

Linker Role

The linker combines multiple object files and libraries, resolves symbols, and produces a single executable. The -o option of gcc creates the final binary, which can then be executed to obtain the expected result.

ELF File Format

On Linux, both executable and object files use the ELF (Executable and Linkable Format). ELF files contain sections such as:

.text : code segment

.data : initialized data

.rel.text : relocation entries for unresolved addresses

.symtab : symbol table mapping names to addresses

The linker builds a global symbol table from all input object files, applies relocations using the relocation table, and merges sections into a final executable where function calls point to correct addresses.

Loader

After linking, the loader reads the ELF header, loads the appropriate sections into memory, and the CPU begins execution. Because the loader understands ELF, it cannot load Windows PE (Portable Executable) binaries.

Cross‑Platform Execution

To run Windows programs on Linux, a loader that understands PE is required. The open‑source project Wine provides such a compatibility layer. Conversely, Windows Subsystem for Linux (WSL) adds an ELF loader to Windows, allowing Linux binaries to run.

Conclusion

The key reason a program runs on Linux but not on Windows is the differing executable formats (ELF vs. PE) and the corresponding loaders. Understanding the compilation, linking, and loading pipeline clarifies how static linking, symbol tables, and relocation enable correct execution.

Recommended Reading

For a deeper dive into linking and ELF, see chapters 1‑4 of “Programmer’s Self‑Cultivation: Linking, Loading, and Libraries”.