错误编译代码 - 'for' 循环初始声明只允许在 C99 模式下

Question

I'm compiling gvmlib with make and this is showing the following error: 'for' loop initial declarations are only allowed in C99 mode.

I used gcc in the code with the --std=c99 and --std=gnu99 option in the code and fatal error appears: glib.h file or directory not found

I installed glib 2.0 and it was working normally

follow the part of the code that is giving error

static element_t find_child(element_t element, const gchar *name)
{
      for (xmlNode *node = element->children; node; node = node->next)
          if (xmlStrcmp(node->name, (const xmlChar *)name) == 0)
              return node;
      return NULL;
}

Answer 1

The compiler option to enable C99 (without changing anything else) is not --std=c99 , it is --std=gnu99 .

If you use --std=c99 you both enable C99 and also disable GNU extensions that were turned on by the default setting (which is --std=gnu89 ).

Of course by now you may want to use --std=gnu11 or --std=gnu18 .