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From: Keith Packard <keithp@keithp.com>
To: libstdc++@gcc.gnu.org
Cc: gcc-patches@gcc.gnu.org,
	Keith Packard <keithp@keithp.com>
Subject: [PATCH 0/2] Support libc with stdio-only I/O in libstdc++
Date: Wed,  9 Dec 2020 18:46:55 -0800
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The current libstdc++ basic_file_stdio.cc code assumes a POSIX API
underneath the stdio implementation provided by the host libc. This
means that the host must provide a fairly broad POSIX file API,
including read, write, open, close, lseek and ioctl.

This patch changes basic_file_stdio.cc to only use basic ANSI-C stdio
functions, allowing it to be used with libc implementations like
picolibc which may not have a POSIX operating system underneath.

This is version 2 of the patch. This version uses the existing
--enable-stdio option, extending that to add 'stdio_pure' for this
mode using a patch created by Jonathan Wakely <jwakely@redhat.com>