如何将带有库导入的C文件编译为Webassembly文件（Emscripten）

Question

我有一个简单的C程序，需要解析Json数据。为此，我已经导入了JSON-C库。我的C代码是-

#include"json.h"
#include <emscripten.h>

EMSCRIPTEN_KEEPALIVE
int addnumbers(int a, int b) {
    FILE *fp;
    char buffer[1024];
    struct json_object *parsed_json;
    struct json_object *name;
    struct json_object *age;
    struct json_object *friends;
    struct json_object *friend;
    size_t n_friends;

    size_t i;

    fp = fopen("test.json","r");
    fread(buffer, 1024, 1, fp);
    fclose(fp);

    parsed_json = json_tokener_parse(buffer); 

    json_object_object_get_ex(parsed_json, "name", &name);
    json_object_object_get_ex(parsed_json, "age", &age);
    json_object_object_get_ex(parsed_json, "friends", &friends);

    printf("Name: %s\n", json_object_get_string(name));
    printf("Age: %d\n", json_object_get_int(age));

    n_friends = json_object_array_length(friends);


    for(i=0;i<n_friends;i++) {
        friend = json_object_array_get_idx(friends, i);
        // printf("%lu. %s\n",i+1,json_object_get_string(friend));
    }
    return n_friends;
}

我遵循的过程是：-使用command-

将库（特别是json.h文件）编译为位代码

emcc json.h -o json.bc

然后使用-编译我的C程序>

emcc json.c -o j_plumbing.bc -s EXTRA_EXPORTED_RUNTIME_METHODS=['ccall','cwrap'] -s ENVIRONMENT='web,worker' -s EXPORT_ES6=1 -s MODULARIZE=1 -s USE_ES6_IMPORT_META=0

然后我一起使用以下命令编译了两个文件以获取wasm文件：-

emcc json.bc j_plumbing.bc -o js_plumbing.js -s EXTRA_EXPORTED_RUNTIME_METHODS=['ccall','cwrap'] -g4 -s LINKABLE=1 -s EXPORT_ALL=1 -s ENVIRONMENT='web,worker' -s EXPORT_ES6=1 -s MODULARIZE=1 -s USE_ES6_IMPORT_META=0 
这就是我从Vue文件中调用它的方式

public draw_outline() {
        Module().then(myModule => {
            console.log(myModule)
            const result = myModule.ccall('addnumbers',
                'number',
                ['number', 'number'],
                [4, 6]);
            console.log("Value from wasm file", result);
        });
    }
but this is the error I'm getting-

002210ee:1 Uncaught (in promise) RuntimeError: function signature mismatch
    at fclose (wasm-function[524]:0x1a777)
    at addnumbers (wasm-function[148]:0x6a45)
    at Module._addnumbers (webpack-internal:///./src/components/js_plumbing.js:1098:4989)
    at Object.ccall (webpack-internal:///./src/components/js_plumbing.js:199:628)
    at eval (webpack-internal:///./node_modules/cache-loader/dist/cjs.js?!./node_modules/babel-loader/lib/index.js!./node_modules/ts-loader/index.js?!./node_modules/cache-loader/dist/cjs.js?!./node_modules/vue-loader/lib/index.js?!./src/components/Extraction.vue?vue&type=script&lang=ts&:128:31)
    at Object.Module.onRuntimeInitialized (webpack-internal:///./src/components/js_plumbing.js:1109:95)
    at doRun (webpack-internal:///./src/components/js_plumbing.js:1117:140)
    at run (webpack-internal:///./src/components/js_plumbing.js:1117:436)
    at runCaller (webpack-internal:///./src/components/js_plumbing.js:1113:15)
    at removeRunDependency (webpack-internal:///./src/components/js_plumbing.js:373:843)
有人能指出我在这里做错了吗？任何帮助表示赞赏

我有一个简单的C程序，需要解析Json数据。为此，我已经导入了JSON-C库。我的C代码是-#include“ json.h” #include EMSCRIPTEN_KEEPALIVE int addnumbers（...

Answer 1