## 2 Command-Line Options

This chapter describes command-line options available in all versions of the GNU assembler; see Machine Dependencies, for options specific to particular machine architectures.

If you are invoking `as` via the GNU C compiler, you can use the ‘`-Wa`’ option to pass arguments through to the assembler. The assembler arguments must be separated from each other (and the ‘`-Wa`’) by commas. For example:

    gcc -c -g -O -Wa,-alh,-L file.c

This passes two options to the assembler: ‘`-alh`’ (emit a listing to standard output with high-level and assembly source) and ‘`-L`’ (retain local symbols in the symbol table).

Usually you do not need to use this ‘`-Wa`’ mechanism, since many compiler command-line options are automatically passed to the assembler by the compiler. (You can call the GNU compiler driver with the ‘`-v`’ option to see precisely what options it passes to each compilation pass, including the assembler.)