在進行網絡編程的過程中，我們經常需要從互聯網上接收JSON數據來處理。而在C語言中，我們可以通過使用一些http庫來實現這個功能。

在這里，我們可以使用Curl庫作為示例，來演示如何在C語言中接收網頁JSON數據。

#include#includestruct MemoryStruct {
char *memory;
size_t size;
};
static size_t WriteMemoryCallback(void *ptr, size_t size, size_t nmemb, void *data)
{
size_t realsize = size * nmemb;
struct MemoryStruct *mem = (struct MemoryStruct *)data;
mem->memory = realloc(mem->memory, mem->size + realsize + 1);
if(mem->memory == NULL) {
/* out of memory! */
printf("not enough memory (realloc returned NULL)\n");
return 0;
}
memcpy(&(mem->memory[mem->size]), ptr, realsize);
mem->size += realsize;
mem->memory[mem->size] = 0;
return realsize;
}
int main(void)
{
CURL *curl_handle;
CURLcode res;
struct MemoryStruct chunk;
chunk.memory = malloc(1); /* will be grown as needed by the realloc above */
chunk.size = 0;           /* no data at this point */
curl_global_init(CURL_GLOBAL_ALL);
/* init the curl session */
curl_handle = curl_easy_init();
/* set URL to get here */
curl_easy_setopt(curl_handle, CURLOPT_URL, "http://example.com/json");
/* send all data to this function  */
curl_easy_setopt(curl_handle, CURLOPT_WRITEFUNCTION, WriteMemoryCallback);
/* we pass our 'chunk' struct to the callback function */
curl_easy_setopt(curl_handle, CURLOPT_WRITEDATA, (void *)&chunk);
/* some servers don't like requests that are made without a user-agent string, so we provide one */
curl_easy_setopt(curl_handle, CURLOPT_USERAGENT, "libcurl-agent/1.0");
/* get it */
res = curl_easy_perform(curl_handle);
/* check for errors */
if(res != CURLE_OK) {
fprintf(stderr, "curl_easy_perform() failed: %s\n", curl_easy_strerror(res));
}
else {
/*
* Now, our chunk.memory points to a memory block that is chunk.size
* bytes big and contains the remote file.
*
* Do something nice with it!
*/
printf("%lu bytes retrieved\n", (long)chunk.size);
}
/* cleanup curl stuff */
curl_easy_cleanup(curl_handle);
free(chunk.memory);
/* we're done with libcurl, so clean it up */
curl_global_cleanup();
return 0;
}

以上是一個簡單的Curl示例，可以通過設定URL來獲取JSON數據，并通過回調函數來處理返回的數據。在回調函數里，我們可以通過處理callback來將返回的數據存儲到內存中。