Hi I write a code to print out "Hello world" in Rust and C to compare binary size. by the way, binary size compiled with rustc is too bigger than in C. I found there are many symbols in Rust binary and it looks like name mangling on C++. Can you please explain why and how to reduce binary size? BR.

Have you searched? This has been posted many times before, and the answer has not changed.

Yes. First of all, you’re probably using different ways. Secondly, did you build with size optimizations? Profile: [profile.release] opt-level = 3 strip = true debug = false lto = true codegen-units = 1 C code: #include main() { puts("Hello, World!"); } Rust code: #![no_main] extern { fn puts(ptr: *const u8); } #[no_mangle] unsafe extern fn main() { puts("Hello, World!\0".as_ptr()); } Rust code seems to be more verbose, does it mean bigger binary size? no, it doesn’t Let’s build our C code with GCC with -O3 flag and our Rust code with -r flag. On windows, GCC gave me 48 kilobytes, while rustc gave 11 kilobytes. Interesting result, huh? You probably were getting bigger binaries because of unwinding, allocations and all the stuff that std does :wink:

Or just the fact that Rust links statically by default for reliability, whereas most modern systems provide a dynamic C standard library and so C compilers tend to link it dynamically.

Code size for hello world Rust vs. C

help

afewgoodman October 28, 2022, 3:02am 3

Oh I see. I will

Thanks.

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Code size for hello world Rust vs. C

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