The directive {$OUTPUT_FORMAT format} has the same functionality as the -A command line option: it tells the compiler what kind of object file must be generated. You can specify this switch only before the Program or Unit clause in your source file. The different kinds of formats are shown in table (1.1).
The default output format depends on the platform the compiler was compiled on.
| Switch value | Generated format |
| AS | AT&T assembler file. |
| AS_AOUT | Go32v1 assembler file. |
| ASW | AT&T Win32 assembler file. |
| COFF | Go32v2 COFF object file. |
| MASM | Masm assembler file. |
| NASM | Nasm assembler file. |
| NASMCOFF | Nasm assembler file (COFF format). |
| NASMELF | Nasm assembler file (ELF format). |
| PECOFF | PECOFF object file (Win32). |
| TASM | Tasm assembler file. |