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i'm following zig's project from HN and i often see cross-compilation and c/c++ mentionned. Why is zig often mentionned in that context ? it seems that cross-c

by bsaul 5y ago

i'm following zig's project from HN and i often see cross-compilation and c/c++ mentionned. Why is zig often mentionned in that context ? it seems that cross-compilation and C can be achieved using llvm/clang without a lot of problem ? What is zig accomplishing in that matter that makes it so special ?

fastball 5y ago
Best place to read more is probably on the Zig project website, specifically this section[1] on how/why Zig's compiler is also a C compiler and the benefits that provides. [1] https://ziglang.org/learn/overview/#zig-is-also-a-c-compiler https://ziglang.org/learn/overview/#zig-is-also-a-c-compiler
- einpoklum 5y ago
  So, I read that, and it is vague about whether the zig compiler itself compiles C, or whether it launches a C compiler (cc). --- I will resist making the obvious reference despite having said both "launch" and "zig" in the same sentence.
  - kristoff_it 5y ago
    https://andrewkelley.me/post/zig-cc-powerful-drop-in-replacement-gcc-clang.html https://andrewkelley.me/post/zig-cc-powerful-drop-in-replace...
  - fastball 5y ago
    The zig compiler itself (which is written in Zig) compiles C, `zig cc` just indicates to the zig compiler to parse C compiler options (`zig cc` has the same interface as Clang).
dralley 5y ago
TL;DR the hardest part of cross compilation is usually getting the tool gains set up to do so. Zig ships a bunch of libc's in a lightweight compressed format which makes cross compilation completely trivial, it handles most of the work behind the scenes.
- BiteCode_dev 5y ago
  How does it hande openssl ?
  - gpanders 5y ago
    What do you mean? It can link against OpenSSL just like any other library. I don’t know if OpenSSL supports static builds, but if it does you can link it statically as well.
    - BiteCode_dev 5y ago
      For cross compilation with dynamic linking I mean. Openssl is typically one you want to be kept up to date with OS updates. Like libc, it can be a pain.
ColonelPhantom 5y ago
llvm/clang does not cross-compile "without a lot of problems". See this post from Zig's creator: https://andrewkelley.me/post/zig-cc-powerful-drop-in-replacement-gcc-clang.html https://andrewkelley.me/post/zig-cc-powerful-drop-in-replace... zig cc uses clang under the hood, and Zig the language is also mostly based on LLVM, but zig cc ships a lot of versions of libc to ensure that it can properly compile to all platforms without weird linker errors.
gpanders 5y ago
Do you have experience cross compiling? If so, you’re likely familiar with the headache: getting the right tool chains, sysroots, compiler flags, libraries, etc. There are entire businesses and open source tools whose raison d'être is providing these tool chains and making the process simpler. With Zig, that all goes away. It’s as simple as saying `zig build -Dtarget=aarch64-linux-gnu` or `zig build -Dtarget=riscv32-freestanding-none` and it just works. It’s pretty incredible. Zig has set the bar for how cross compilation should be done and all other languages should be measured against it. Rust is close but is still a headache. The only other language that compares at the moment (IMO) is Go.
- HowardStark 5y ago
  Huh. From what you said and then a quick peek at the docs Zig does seem great in that regard, but in my own experience I’ve definitely found Rust to be equally competent. What about Zig would you say makes it better? Rust has `cargo build --target <triple>`
  - mlindner 5y ago
    From what I've heard, for Rust the difficulty comes in when you're using a Rust wrapper of a C/C++ library and you need to crosscompile both into the binary.
  - gpanders 5y ago
    Admittedly I don’t have as much experience cross compiling with Rust, but my experience has not been so smooth. You need to install each target toolchain manually with rustup, and then some tool chains require different versions of Rust (e.g. the ESP32 RISC-V toolchain requires nightly). Another time I tried cross compiling on x86 Linux targeting Linux on ARM64, and I kept getting linking errors (or it couldn’t find an acceptable linker). I certainly agree that Rust is much better than C/C++, but it’s not quite at Zig level, at least in my (limited) experience.
  - zamadatix 5y ago
    Cross compiling for the language itself is half of it, albeit a half Rust does decently well too, but Zig will also cross compile C/C++ for you just as easily. The latter part combined with Zig's focus on making it as 0 effort as possible to do either action is what results in it being talked about so much.
defen 5y ago
Here's the problem statement in a nutshell. Consider the following trivial C program: #include <stdio.h> #include <sys/random.h> int main(void) { unsigned char buf[10]; ssize_t ret; ret = getrandom(buf, sizeof(buf), 0); if (ret != sizeof(buf)) fprintf(stderr, "getrandom() failed\n"); else fprintf(stderr, "getrandom() success\n"); return ret != sizeof(buf); } You have an x86_64 Linux machine running glibc 2.17. Your task is to compile the above program into a dynamically linked executable targeting glibc 2.28 on x86_64 Linux. With Zig, it looks like this: 1) Download zig 2) `zig cc -target x86_64-linux-gnu.2.28 random.c` What would those steps look like using llvm/clang? Next, try doing it from Windows 8
- charcircuit 5y ago
  It's simpler with clang. clang random.c glibc 2.28 will work with binaries compiled against 2.17.
  - mappu 5y ago
    Unfortunately that won't compile against glibc 2.17 since getrandom(2) was only added to glibc in 2.25. See https://lwn.net/Articles/711013/ https://lwn.net/Articles/711013/ for background info,
    - charcircuit 5y ago
      nvm then

by bsaul 5y ago

fastball 5y ago

Best place to read more is probably on the Zig project website, specifically this section[1] on how/why Zig's compiler is also a C compiler and the benefits that provides. [1] https://ziglang.org/learn/overview/#zig-is-also-a-c-compiler https://ziglang.org/learn/overview/#zig-is-also-a-c-compiler

einpoklum 5y ago
So, I read that, and it is vague about whether the zig compiler itself compiles C, or whether it launches a C compiler (cc). --- I will resist making the obvious reference despite having said both "launch" and "zig" in the same sentence.
- kristoff_it 5y ago
  https://andrewkelley.me/post/zig-cc-powerful-drop-in-replacement-gcc-clang.html https://andrewkelley.me/post/zig-cc-powerful-drop-in-replace...
- fastball 5y ago
  The zig compiler itself (which is written in Zig) compiles C, `zig cc` just indicates to the zig compiler to parse C compiler options (`zig cc` has the same interface as Clang).

dralley 5y ago

TL;DR the hardest part of cross compilation is usually getting the tool gains set up to do so. Zig ships a bunch of libc's in a lightweight compressed format which makes cross compilation completely trivial, it handles most of the work behind the scenes.

BiteCode_dev 5y ago
How does it hande openssl ?
- gpanders 5y ago
  What do you mean? It can link against OpenSSL just like any other library. I don’t know if OpenSSL supports static builds, but if it does you can link it statically as well.
  - BiteCode_dev 5y ago
    For cross compilation with dynamic linking I mean. Openssl is typically one you want to be kept up to date with OS updates. Like libc, it can be a pain.

ColonelPhantom 5y ago

llvm/clang does not cross-compile "without a lot of problems". See this post from Zig's creator: https://andrewkelley.me/post/zig-cc-powerful-drop-in-replacement-gcc-clang.html https://andrewkelley.me/post/zig-cc-powerful-drop-in-replace... zig cc uses clang under the hood, and Zig the language is also mostly based on LLVM, but zig cc ships a lot of versions of libc to ensure that it can properly compile to all platforms without weird linker errors.

gpanders 5y ago

Do you have experience cross compiling? If so, you’re likely familiar with the headache: getting the right tool chains, sysroots, compiler flags, libraries, etc. There are entire businesses and open source tools whose raison d'être is providing these tool chains and making the process simpler. With Zig, that all goes away. It’s as simple as saying `zig build -Dtarget=aarch64-linux-gnu` or `zig build -Dtarget=riscv32-freestanding-none` and it just works. It’s pretty incredible. Zig has set the bar for how cross compilation should be done and all other languages should be measured against it. Rust is close but is still a headache. The only other language that compares at the moment (IMO) is Go.

HowardStark 5y ago
Huh. From what you said and then a quick peek at the docs Zig does seem great in that regard, but in my own experience I’ve definitely found Rust to be equally competent. What about Zig would you say makes it better? Rust has `cargo build --target <triple>`
- mlindner 5y ago
  From what I've heard, for Rust the difficulty comes in when you're using a Rust wrapper of a C/C++ library and you need to crosscompile both into the binary.
- gpanders 5y ago
  Admittedly I don’t have as much experience cross compiling with Rust, but my experience has not been so smooth. You need to install each target toolchain manually with rustup, and then some tool chains require different versions of Rust (e.g. the ESP32 RISC-V toolchain requires nightly). Another time I tried cross compiling on x86 Linux targeting Linux on ARM64, and I kept getting linking errors (or it couldn’t find an acceptable linker). I certainly agree that Rust is much better than C/C++, but it’s not quite at Zig level, at least in my (limited) experience.
- zamadatix 5y ago
  Cross compiling for the language itself is half of it, albeit a half Rust does decently well too, but Zig will also cross compile C/C++ for you just as easily. The latter part combined with Zig's focus on making it as 0 effort as possible to do either action is what results in it being talked about so much.

defen 5y ago

Here's the problem statement in a nutshell. Consider the following trivial C program: #include <stdio.h> #include <sys/random.h> int main(void) { unsigned char buf[10]; ssize_t ret; ret = getrandom(buf, sizeof(buf), 0); if (ret != sizeof(buf)) fprintf(stderr, "getrandom() failed\n"); else fprintf(stderr, "getrandom() success\n"); return ret != sizeof(buf); } You have an x86_64 Linux machine running glibc 2.17. Your task is to compile the above program into a dynamically linked executable targeting glibc 2.28 on x86_64 Linux. With Zig, it looks like this: 1) Download zig 2) `zig cc -target x86_64-linux-gnu.2.28 random.c` What would those steps look like using llvm/clang? Next, try doing it from Windows 8

charcircuit 5y ago
It's simpler with clang. clang random.c glibc 2.28 will work with binaries compiled against 2.17.
- mappu 5y ago
  Unfortunately that won't compile against glibc 2.17 since getrandom(2) was only added to glibc in 2.25. See https://lwn.net/Articles/711013/ https://lwn.net/Articles/711013/ for background info,
  - charcircuit 5y ago
    nvm then