digitalmars.D.learn - extern (c)
- Paul (7/7) Oct 11 2023 What does the extern (c) attribute(?) do?
- Ferhat =?UTF-8?B?S3VydHVsbXXFnw==?= (4/11) Oct 11 2023 It is about name mangling. It prevents symbol names from using
- user1234 (6/13) Oct 11 2023 `extern(C)` on module level functions affect the mangling and the
- Paul (6/12) Oct 11 2023 So C doesn't use name mangling and extern (C) in a D prog would
- user1234 (6/20) Oct 11 2023 I see what you mean. I just consider no mangling as a kind of
- Imperatorn (2/16) Oct 11 2023 https://dlang.org/spec/abi.html
What does the extern (c) attribute(?) do? Does it tell the compiler/linker to build the function like a C compiler would build a C function? If so what does that mean? Does it tell the compiler/linker to let C functions know it exists? If so what does that mean? Is it meant for the compiler or linker or both? Thanks for any assistance.
Oct 11 2023
Ferhat =?UTF-8?B?S3VydHVsbXXFnw==?= <aferust gmail.com> On Wednesday, 11 October 2023 at 12:36:58 UTC, Paul wrote:What does the extern (c) attribute(?) do? Does it tell the compiler/linker to build the function like a C compiler would build a C function? If so what does that mean? Does it tell the compiler/linker to let C functions know it exists? If so what does that mean? Is it meant for the compiler or linker or both? Thanks for any assistance.It is about name mangling. It prevents symbol names from using D's name mangling. https://dlang.org/blog/2017/12/20/ds-newfangled-name-mangling/
Oct 11 2023
On Wednesday, 11 October 2023 at 12:36:58 UTC, Paul wrote:What does the extern (c) attribute(?) do? Does it tell the compiler/linker to build the function like a C compiler would build a C function? If so what does that mean? Does it tell the compiler/linker to let C functions know it exists? If so what does that mean? Is it meant for the compiler or linker or both? Thanks for any assistance.`extern(C)` on module level functions affect the mangling and the calling convention. - Mangling is used by the linker to link symbols between objects. - Calling convention affects the compiler backend in how code is generated for a CALL instruction.
Oct 11 2023
On Wednesday, 11 October 2023 at 12:54:53 UTC, user1234 wrote:`extern(C)` on module level functions affect the mangling and the calling convention. - Mangling is used by the linker to link symbols between objects. - Calling convention affects the compiler backend in how code is generated for a CALL instruction.So C doesn't use name mangling and extern (C) in a D prog would turn off D mangling thereby allowing C and D object files to be linked together? I didn't know C and D had different calling conventions...i.e. different ABI's?
Oct 11 2023
On Wednesday, 11 October 2023 at 13:36:16 UTC, Paul wrote:On Wednesday, 11 October 2023 at 12:54:53 UTC, user1234 wrote:I see what you mean. I just consider no mangling as a kind of mangling, that is "just the symbol name".`extern(C)` on module level functions affect the mangling and the calling convention. - Mangling is used by the linker to link symbols between objects. - Calling convention affects the compiler backend in how code is generated for a CALL instruction.So C doesn't use name manglingand extern (C) in a D prog would turn off D mangling thereby allowing C and D object files to be linked together? I didn't know C and D had different calling conventions...i.e. different ABI's?They are mostly similar but according to https://dlang.org/spec/abi.html#function_calling_conventions there are differences.
Oct 11 2023
On Wednesday, 11 October 2023 at 13:36:16 UTC, Paul wrote:On Wednesday, 11 October 2023 at 12:54:53 UTC, user1234 wrote:https://dlang.org/spec/abi.html`extern(C)` on module level functions affect the mangling and the calling convention. - Mangling is used by the linker to link symbols between objects. - Calling convention affects the compiler backend in how code is generated for a CALL instruction.So C doesn't use name mangling and extern (C) in a D prog would turn off D mangling thereby allowing C and D object files to be linked together? I didn't know C and D had different calling conventions...i.e. different ABI's?
Oct 11 2023