编译cJSON.c报警告，怎么改？

发布于 2019-02-10 14:45:04 浏览：4895 订阅该版

编译后
```
*** Using Compiler 'V5.06 update 6 (build 750)', folder: 'E:\Software\Keil_v5\ARM\ARMCC\Bin'
Build target 'rt-thread'
compiling cJSON.c...
packages\EasyFlash-latest\plugins\types\struct2json\src\cJSON.c(55): warning:  #1293-D: assignment in condition
        if (!(copy = (char*)cJSON_malloc(len))) return 0;
packages\EasyFlash-latest\plugins\types\struct2json\src\cJSON.c(279): warning:  #1293-D: assignment in condition
      ptr=str;while ((token=*ptr) && ++len) {if (strchr("\"\\\b\f<br> \t",token)) len++; else if (token<32) len+=5;ptr++;}
packages\EasyFlash-latest\plugins\types\struct2json\src\cJSON.c(353): warning:  #111-D: statement is unreachable
      return p.buffer;
packages\EasyFlash-latest\plugins\types\struct2json\src\cJSON.c(424): warning:  #1293-D: assignment in condition
          if (!(new_item=cJSON_New_Item())) return 0;     /* memory fail */
packages\EasyFlash-latest\plugins\types\struct2json\src\cJSON.c(536): warning:  #1293-D: assignment in condition
          if (!(new_item=cJSON_New_Item()))    return 0; /* memory fail */
packages\EasyFlash-latest\plugins\types\struct2json\src\cJSON.c: 5 warnings, 0 errors
```

这些错误是while/if判断时 不是布尔型的 导致的 那么需要改吗？怎么改呢？

比如说这个
```c
        cJSON *new_item;
        if (!(new_item=cJSON_New_Item())) return 0;     /* memory fail */
```
可以这么改吗？-> `if ((new_item=cJSON_New_Item())==NULL) return 0; `

还是这么改-> `if ((new_item=cJSON_New_Item())==cJSON_NULL) return 0; // cJSON_NULL = 2`

而且有个函数居然有连着的return
```c
char *cJSON_PrintBuffered(cJSON *item,int prebuffer,int fmt)
{
        printbuffer p;
        p.buffer=(char*)cJSON_malloc(prebuffer);
        p.length=prebuffer;
        p.offset=0;
        <font color="Red">return print_value(item,0,fmt,&p);
        return p.buffer;</font>
}
```