[SOLVED] Why does it say "We must not include limits.h!" in dirent.h?

Why does it say "We must not include limits.h!" in dirent.h?

When we include <dirent.h> and <limits.h> to a c file, dirent structs' d_name variable shows We must not include limits.h! in the variable description in the ide. When I look at the file /usr/include/x86_64-linux-gnu/bits/dirent.h it contains the following code piece.

...
struct dirent
  {
#ifndef __USE_FILE_OFFSET64
    __ino_t d_ino;
    __off_t d_off;
#else
    __ino64_t d_ino;
    __off64_t d_off;
#endif
    unsigned short int d_reclen;
    unsigned char d_type;
    char d_name[256];       /* We must not include limits.h! */
  };
...

My question is why we must not include limits.h. I've searched online, but I couldn't find any satisfying answer.

Solution

Each standard header has a specification for what it exposes or may expose. dirent.h exposes struct dirent, DIR, and the relevant functions, and reserves names starting with d_. Some headers are also permitted but not required to expose things exposed by certain other headers; dirent.h is not one of these. So indirectly including limits.h would be a violation of the namespace and would break conforming programs that assume they can use names that limits.h would expose for their own identifiers.