Re: supporting strings > 2 GB

[Bruno Haible <bruno@clisp.org>]

Hi Paul,

Probably I didn't explain it well. Let me try again.

> Gnulib may need something like printf_len_t, PRIdPRINTF etc., but I don't quite 
> see why POSIX and/or the C standard would need them.

The code will consist of two layers:

1) A layer that defines functions.
   Example:
     ptrdiff_t lprintf (const char *format, ...)
     _GL_ATTRIBUTE_FORMAT_PRINTF (1, 2);

2) A layer that may redefine functions and types through aliases.
   Example:
     #if _PRINTF_LARGE
       #undef printf
       #define printf lprintf
       #define printf_len_t ptrdiff_t
     #else
       #define printf_len_t int
     #endif

This is similar to how the large file support was implemented
in two layers:

1) A function
     off64_t lseek64(int fd, off64_t offset, int whence);

2) A layer that redefines functions and types:

     #if _FILE_OFFSET_BITS == 64
       #define lseek lseek64
       #define off_t off64_t
     #endif

The C or POSIX standards deal only with layer 1). However, layer 2) is
essential for programs, to make the use of the new APIs easy.

Bruno