C語言作為一門廣泛應用的編程語言，其內置函數庫也相當豐富。對于開發人員而言，有時候需要接收JSON數據類型的POST請求。接下來，我們將通過C語言的內置函數庫來實現這個需求。

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <curl/curl.h>
struct MemoryStruct {
char *memory;
size_t size;
};
static size_t WriteMemoryCallback(void *contents, size_t size, size_t nmemb, void *userp) {
size_t realsize = size * nmemb;
struct MemoryStruct *mem = (struct MemoryStruct *)userp;
mem->memory = realloc(mem->memory, mem->size + realsize + 1);
if(mem->memory == NULL)
return 0;
memcpy(&(mem->memory[mem->size]), contents, realsize);
mem->size += realsize;
mem->memory[mem->size] = 0;
return realsize;
}
int main(void) {
CURL *curl;
CURLcode res;
curl = curl_easy_init();
if(curl) {
struct MemoryStruct chunk;
chunk.memory = malloc(1);
chunk.size = 0;
curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/receivejson");
curl_easy_setopt(curl, CURLOPT_POSTFIELDS, "{\"key\":\"value\"}");
curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, WriteMemoryCallback);
curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void *)&chunk);
res = curl_easy_perform(curl);
if(res != CURLE_OK)
fprintf(stderr, "curl_easy_perform() failed: %s\n", curl_easy_strerror(res));
else
printf("%lu bytes retrieved\n", (unsigned long)chunk.size);
free(chunk.memory);
curl_easy_cleanup(curl);
}
return 0;
}

在上述代碼中，我們首先引入了“curl/curl.h”頭文件，來實現CURL發送POST請求。接下來，創建了一個WriteMemoryCallback函數來存儲接收到的JSON數據。使用curl_easy_setopt方法設置請求的URL、POST數據、回調函數和回調參數。最后通過curl_easy_perform方法發送請求?？梢钥吹?，使用C語言非常簡單地實現了接收JSON數據類型的POST請求的功能。