如何解决“右侧操作数无效”错误？

我目前正在使用Eclipse CDT，ESP-IDF框架和ESP32 Wrover DevKit。

我一直在寻找一种C矢量实现，在GitHub上偶然发现了rxi / vec。我复制vec.h并复制vec.c到我的项目中，并尝试进行编译。我收到以下错误：

Error: right-hand operand of comma expression has no effect[-Werror=unused-value]

...在这行代码中vec.h：

#define vec_push(v, val)\
  ( vec_expand_(vec_unpack_(v)) ? -1 :\
    ((v)->data[(v)->length++] = (val), 0), 0 )

任何想法如何解决这个问题或解决？任何替代向量实现C？

更新A

../main/tools/inc/vec.h:35:42: error: right-hand operand of comma expression has no effect [-Werror=unused-value]
   ( vec_expand_(vec_unpack_(v)) ? -1 :\
   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~   
     ((v)->data[(v)->length++] = (val), 0), 0 )
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~
../main/main.c:44:2: note: in expansion of macro 'vec_push'
  vec_push(&toc.items, item1);
  ^~~~~~~~
../main/tools/inc/vec.h:35:42: error: right-hand operand of comma expression has no effect [-Werror=unused-value]
   ( vec_expand_(vec_unpack_(v)) ? -1 :\
   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~   
     ((v)->data[(v)->length++] = (val), 0), 0 )
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~
../main/main.c:50:2: note: in expansion of macro 'vec_push'
  vec_push(&item1.elements, elem1);
  ^~~~~~~~
../main/tools/inc/vec.h:35:42: error: right-hand operand of comma expression has no effect [-Werror=unused-value]
   ( vec_expand_(vec_unpack_(v)) ? -1 :\
   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~   
     ((v)->data[(v)->length++] = (val), 0), 0 )
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~
../main/main.c:56:2: note: in expansion of macro 'vec_push'
  vec_push(&item1.elements, elem2);
  ^~~~~~~~
cc1: some warnings being treated as errors

更新B

#include <stdio.h>
#include <stdlib.h>
#include "vec.h"

typedef struct toc_element_t {
  uint16_t uid;
  char element[8];
  char type[8];
} toc_element_t;

typedef vec_t(toc_element_t) vec_toc_element_t;

typedef struct toc_item_t {
  char category[8];
  vec_toc_element_t elements;
} toc_item_t;

typedef vec_t(toc_item_t) vec_toc_item_t;

typedef struct toc_t {
    char description[8];
    vec_toc_item_t items;
} toc_t;


void app_main(void) {

    toc_t toc;
    strcpy(toc.description, "toc1");
    vec_init(&toc.items);

    toc_item_t item1;
    strcpy(item1.category, "cat1");
    vec_init(&item1.elements);
    vec_push(&toc.items, item1);

    toc_element_t elem1;
    elem1.uid=0;
    strcpy(elem1.element, "elem1");
    strcpy(elem1.type, "float");
    vec_push(&item1.elements, elem1);

    toc_element_t elem2;
    elem2.uid=1;
    strcpy(elem2.element, "elem2");
    strcpy(elem2.type, "float");
    vec_push(&item1.elements, elem2);


    printf("TOC [%s]:\n", toc.description);

    toc_item_t item; int index1;
    vec_foreach(&toc.items, item, index1) {
        printf(" - item[%d]=%s\n", index1, item.category);
        toc_element_t element; int index2;
        vec_foreach(&item.elements, element, index2) {
            printf("  - element[%d]=%s [%s]\n", index2, element.element, element.type);
        }
    }

    while(1);

}

更新C

也许这个问题与这个问题无关，但是由于Eric在上次提交时提到了日志消息“针对结构体修复了vec_insert（）和vec_push（）”，并插入了,0导致此处讨论的问题的“腥” ，因此可能是有关。

当执行“更新B”部分中的代码时，我得到以下输出：

TOC [toc1]:
 - item[0]=cat1

但我期望以下几点：

TOC [toc1]:
 - item[0]=cat1
  - element[0]=elem1
  - element[1]=elem2

已解决：为什么内部矢量无法打印出来？