CODEWITHSUNDEEP
cwindowsclang
bartc
bartc

Reputation: 324

Is clang a standalone C compiler or does it need gcc?

I want to use clang on Windows to compile C code.

I'd like to know if it is in fact a standalone compiler that can do that, or are its aims somewhat different?

I've used it before, but it appears now that is was piggy-backing on top of whatever gcc compilers were lying around (mingw for example).

If I try a fresh binary installation of clang 64-bits (and I hide my mingw/gcc directories), then it can't find stdio.h for Hello World. This is running from directly inside the bin directory (C:\clang\bin). If I unhide mingw, it will compile, but then I get errors like this (one mingw compiler is in c:\win):

c:\win\bin\ld.exe cannot find -lgcc_s

Considering clang is a 438MB installation, you'd think it would have it's own include and library files! I want to use clang in place of gcc.

So, what am I doing wrong? (I've seen a few questions also about the inability to find stdio.h, but they weren't helpful. Surely clang must be able to compile Hello World by itself?!)

Upvotes: 3

Views: 5802

Answers (3)

Rouven
Rouven

Reputation: 1

I think you are missing a path variable. After install you must manually add a PATH to the Windows Environment.

Upvotes: -2

lvella
lvella

Reputation: 13481

You are confusing compiler with linker with standard library.

Clang is a full featured independent compiler. But it does not provides the standard library (the library containing stdio.h). Traditionally, on Unix systems, the operating systems must provide the standard library it uses. But since you are using Windows, it doesn't, and for whatever reason it finds the ones from MingW installed. There are many free implementations of C standard library which are compatible with Clang.

Lastly, ld.exe is the linker, and it also, traditionally, must be provided by the system. There is one linker, lld, that I believe is being developed alongside Clang, but for whatever reason, the packager of the version you downloaded just chose to configure clang to simply call ld.

Upvotes: 3

cyphar
cyphar

Reputation: 2890

Clang is a completely separate compiler (written entirely from scratch, using LLVM). You don't need GCC to use Clang, as can be shown in the case of FreeBSD (they completely replaced GCC with Clang/LLVM and don't install GCC in the base anymore for licensing reasons). There are a variety of different C compilers other than GCC, it's just that GCC is the most common.

However, no compiler provides the standard C libraries (GCC provides some weird libraries like the one you're trying to use). C libraries are provided separately, and you need to install C libraries in order to compile any significant C program. The error message saying cannot find -lgcc_s tells me that you're trying to link against some library provided by GCC. In this case, you probably want to install that library by installing GCC (but note that you don't need GCC to use Clang.

It does appear that your version of Clang has been compiled to use GNU's linked ld, not LLVM's linked lld. As such, you'll need GCC's linker (or you can recompile clang to use LLVM's linker, or just compile the object files and use lld separately).

Upvotes: 1

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