esp-idf/components/esp_rom/include/esp32c2/rom/newlib.h

/*
 * SPDX-FileCopyrightText: 2020-2022 Espressif Systems (Shanghai) CO LTD
 *
 * SPDX-License-Identifier: Apache-2.0
 */
#pragma once

#include <sys/lock.h>
#include <sys/reent.h>

#ifdef __cplusplus
extern "C" {
#endif

/* Global variables used by newlib in ROM

   Note that any of these symbols which are used by both ROM & IDF will have duplicate copies
   in each "side" of the memory. However they're all pointers, and the pointers will be to the same
   thing, so it's not a big memory waste and functionality is the same.

   Some variables which look like they should be here, but aren't:

   - __sf_fake_stdin, __sf_fake_stdout, __sf_fake_stderr - These are defined in ROM because ROM includes findfp.c,
   but only used if _REENT_INIT or _REENT_INIT_PTR are ever called and ROM doesn't use these macros anywhere unless
   printf() or similar is called without initializing reent first. ESP-IDF sets up its own minimal reent structures.

   - __lock___sinit_recursive_mutex, etc. - these are combined into common_recursive_mutex & common_mutex to save space
*/
typedef struct {
    _LOCK_T common_recursive_mutex;
    _LOCK_T common_mutex;
    struct _reent *global_reent;
} esp_rom_newlib_global_data_t;

/* Called from IDF newlib component setup
   to initialize common data shared between ROM and IDF
*/
void esp_rom_newlib_init_global_data(const esp_rom_newlib_global_data_t *data);

#ifdef __cplusplus
}
#endif