esp-idf/components/newlib/reent_init.c

// Copyright 2015-2016 Espressif Systems (Shanghai) PTE LTD
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include <string.h>
#include <sys/reent.h>
#include "esp_attr.h"

/* This function is not part on newlib API, it is defined in libc/stdio/local.h
 * There is no nice way to get __cleanup member populated while avoiding __sinit,
 * so extern declaration is used here.
 */
extern void _cleanup_r(struct _reent* r);

/**
 * This is the replacement for newlib's _REENT_INIT_PTR and __sinit.
 * The problem with __sinit is that it allocates three FILE structures
 * (stdin, stdout, stderr). Having individual standard streams for each task
 * is a bit too much on a small embedded system. So we point streams
 * to the streams of the global struct _reent, which are initialized in
 * startup code.
 */
void IRAM_ATTR esp_reent_init(struct _reent* r)
{
    memset(r, 0, sizeof(*r));
    r->_stdout = _GLOBAL_REENT->_stdout;
    r->_stderr = _GLOBAL_REENT->_stderr;
    r->_stdin  = _GLOBAL_REENT->_stdin;
    r->__cleanup = &_cleanup_r;
    r->__sdidinit = 1;
    r->__sglue._next = NULL;
    r->__sglue._niobs = 0;
    r->__sglue._iobs = NULL;
    r->_current_locale = "C";
}