esp_predef.h

#include <stdio.h>
#include <stdarg.h>
#include "ets_rom.h"
 
int ets_vsprintf(char *str, const char *format, va_list ap);
 
int tolower(int c);
int toupper(int c);
int isprint(int c);
int islower(int c);
int isupper(int c);
int isalpha(int c);
int isdigit(int c);
int isspace(int c);