Re: Linking D with C structs
On Monday, 29 June 2020 at 10:44:16 UTC, kinke wrote: On Monday, 29 June 2020 at 06:29:38 UTC, Anthony wrote: What does "__initZ" refer to? Does this refer to automatic initialization like "this()"? Almost, it's the static initializer for that struct, which is omitted because you apparently don't compile/link the module containing the struct declaration. Initialize the char array with zeros (= 0) to make the struct fully zero-initialized, preventing the need for that symbol. chars in D are initialized with 0xFF, unlike byte and ubyte. Thanks for this! What do you mean by "which is omitted because you apparently don't compile/link the module containing the struct declaration"? Is there a link step that I'm missing that will make things easier for me? Is there a way to have D automatically get the struct from the c files directly?
Re: Linking D with C structs
On Monday, 29 June 2020 at 06:29:38 UTC, Anthony wrote: What does "__initZ" refer to? Does this refer to automatic initialization like "this()"? Almost, it's the static initializer for that struct, which is omitted because you apparently don't compile/link the module containing the struct declaration. Initialize the char array with zeros (= 0) to make the struct fully zero-initialized, preventing the need for that symbol. chars in D are initialized with 0xFF, unlike byte and ubyte.
Linking D with C structs
Hello,
I'm trying to hand write some bindings to mongo-c-driver. (For
learning purposes and to get the latest bindings).
My binding code to convert to mongoc/mongoc.d
is:
= c interop file
module mongoc/mongoc.d;
import core.stdc.stdint;
extern (c) {
struct {
uint domain;
uint code;
char[504] message; //when this exists, the code does not
compile
}
}
===
= build script
export
LD_LIBRARY_PATH=mongo-c-driver/cmake-build/src/libmongoc:mongo-c-driver/cmake-build/src/libbson:$LD_LIBRARY_PATH
dmd hello_mongo.d \
-I=mongo-c-driver/src/libmongoc/src/ \
-I=mongo-c-driver/src/libbson/src/ \
-I=mongo-c-driver/cmake-build/src/libbson/src/bson/ \
-I=mongo-c-driver/cmake-build/src/libmongoc/src/mongoc \
-L=-Lmongo-c-driver/cmake-build/src/libmongoc \
-L=-Lmongo-c-driver/cmake-build/src/libbson \
-L=-lmongoc-1.0 \
-L=-lbson-1.0 \
./hello_mongo
However, when I add the message field in the struct, I cannot
compile the code:
ld: hello_mongo.o: in function `_Dmain':
hello_mongo.d:(.text._Dmain[_Dmain]+0x1a): undefined reference to
`_D6mongoc6mongoc13_bson_error_t6__initZ'
What does "__initZ" refer to?
Does this refer to automatic initialization like "this()"?
