[libc] add RT_USING_INTERNAL_LIBC_ONLY macro

This option is for RT-Thread Nano version.
If select this option, it will not compile components/libc
folder and only use tool chain internal libc. Normally, the
tool chain internal is only cover ISO standard (e.g. armcc),
but some tool chains' internal libc will cover more than
ISO standard (e.g. newlib).

components/libc/Kconfig

@@ -1,11 +1,27 @@
 menu "C/C++ and POSIX layer"
 
-# This is for external libc(e.g. mlib),
-# and NOT for newlib or picolibc which are inherent in the toolchains.
-# Usually, the external libc should be a software package and select
-# RT_USING_EXTERNAL_LIBC in software package's Kconfig
+config RT_USING_INTERNAL_LIBC_ONLY
+    bool "Only use tool chain internal libc"
+    default n
+    help
+        This option is for RT-Thread Nano version.
+        If select this option, it will not compile components/libc
+        folder and only use tool chain internal libc. Normally, the
+        tool chain internal is only cover ISO standard (e.g. armcc),
+        but some tool chains' internal libc will cover more than
+        ISO standard (e.g. newlib). However, no matter the cover level
+        it is, the rt-thread libc leveling layer will not be involved
+        at all if select this option.
+
 config RT_USING_EXTERNAL_LIBC
+    depends on !RT_USING_INTERNAL_LIBC_ONLY
     bool
+    help
+        This is for external libc(e.g. mlib),
+        and NOT for newlib or picolibc which are inherent in the toolchains.
+        Usually, the external libc should be a software package and select
+        RT_USING_EXTERNAL_LIBC in software package's Kconfig
+        This option is not available for users to select.
 
 source "$RTT_DIR/components/libc/compilers/common/Kconfig"
 source "$RTT_DIR/components/libc/posix/Kconfig"

components/libc/compilers/SConscript

@@ -7,9 +7,10 @@ cwd = GetCurrentDir()
 objs = []
 list = os.listdir(cwd)
 
-for d in list:
-    path = os.path.join(cwd, d)
-    if os.path.isfile(os.path.join(path, 'SConscript')):
-        objs = objs + SConscript(os.path.join(d, 'SConscript'))
+if not GetDepend('RT_USING_INTERNAL_LIBC_ONLY'):
+    for d in list:
+        path = os.path.join(cwd, d)
+        if os.path.isfile(os.path.join(path, 'SConscript')):
+            objs = objs + SConscript(os.path.join(d, 'SConscript'))
 
 Return('objs')

include/rtdef.h

@@ -50,9 +50,9 @@
  * 2023-04-01     Chushicheng  change version number to v5.0.1
  * 2023-05-20     Bernard      add stdc atomic detection.
  * 2023-09-15     xqyjlj       perf rt_hw_interrupt_disable/enable
- * 2023-09-17     Meco Man     add RT_USING_LIBC_ISO_ONLY macro
  * 2023-10-10     Chushicheng  change version number to v5.1.0
  * 2023-10-11     zmshahaha    move specific devices related and driver to components/drivers
+ * 2023-11-21     Meco Man     add RT_USING_INTERNAL_LIBC_ONLY macro
  */
 
 #ifndef __RT_DEF_H__
@@ -60,24 +60,26 @@
 
 #include <rtconfig.h>
 
-#ifdef RT_USING_LIBC
-#if !defined(RT_USING_LIBC_ISO_ONLY) && !defined(RT_VER_NUM)
-/* If RT_VER_NUM is not defined, there is no extra libc support. */
-#define RT_USING_LIBC_ISO_ONLY  (1)
+/*
+ * If RT_VER_NUM is not defined or RT_USING_INTERNAL_LIBC_ONLY is defined,
+ * there is no extra libc support, only internal libc can be used.
+ */
+#if defined(RT_USING_INTERNAL_LIBC_ONLY) || !defined(RT_VER_NUM)
+#define __RT_USING_INTERNAL_LIBC_ONLY  (1)
 #else
-#define RT_USING_LIBC_ISO_ONLY  (0)
-#endif /* !defined(RT_USING_LIBC_ISO_ONLY) && !defined(RT_VER_NUM) */
+#define __RT_USING_INTERNAL_LIBC_ONLY  (0)
+#endif /* defined(RT_USING_INTERNAL_LIBC_ONLY) && !defined(RT_VER_NUM) */
+
 #include <stdint.h>
 #include <stddef.h>
 #include <stdarg.h>
-#if !RT_USING_LIBC_ISO_ONLY
+#if !__RT_USING_INTERNAL_LIBC_ONLY
 #include <sys/types.h>
 #include <sys/errno.h>
 #if defined(RT_USING_SIGNALS) || defined(RT_USING_SMART)
 #include <sys/signal.h>
 #endif /* defined(RT_USING_SIGNALS) || defined(RT_USING_SMART) */
-#endif /* !RT_USING_LIBC_ISO_ONLY */
-#endif /* RT_USING_LIBC */
+#endif /* !__RT_USING_INTERNAL_LIBC_ONLY */
 
 #ifdef __cplusplus
 extern "C" {
@@ -133,13 +135,13 @@ typedef unsigned long long              rt_uint64_t;    /**< 64bit unsigned inte
 #endif /* RT_USING_LIBC */
 #endif /* RT_USING_ARCH_DATA_TYPE */
 
-#if defined(RT_USING_LIBC) && !RT_USING_LIBC_ISO_ONLY
+#if defined(RT_USING_LIBC) && !__RT_USING_INTERNAL_LIBC_ONLY
 typedef size_t                          rt_size_t;      /**< Type for size number */
 typedef ssize_t                         rt_ssize_t;     /**< Used for a count of bytes or an error indication */
 #else
 typedef rt_ubase_t                      rt_size_t;      /**< Type for size number */
 typedef rt_base_t                       rt_ssize_t;     /**< Used for a count of bytes or an error indication */
-#endif /* defined(RT_USING_LIBC) && !RT_USING_LIBC_ISO_ONLY */
+#endif /* defined(RT_USING_LIBC) && !__RT_USING_INTERNAL_LIBC_ONLY */
 
 typedef rt_base_t                       rt_err_t;       /**< Type for error number */
 typedef rt_uint32_t                     rt_time_t;      /**< Type for time stamp */
@@ -403,7 +405,7 @@ typedef int (*init_fn_t)(void);
 /**@{*/
 
 /* RT-Thread error code definitions */
-#if defined(RT_USING_LIBC) && !RT_USING_LIBC_ISO_ONLY
+#if defined(RT_USING_LIBC) && !__RT_USING_INTERNAL_LIBC_ONLY
 /* POSIX error code compatible */
 #define RT_EOK                          0               /**< There is no error */
 #define RT_ERROR                        255             /**< A generic/unknown error happens */
@@ -438,7 +440,7 @@ typedef int (*init_fn_t)(void);
 #define RT_EPERM                        13              /**< Operation not permitted */
 #define RT_ETRAP                        14              /**< Trap event */
 #define RT_EFAULT                       15              /**< Bad address */
-#endif /* defined(RT_USING_LIBC) && !RT_USING_LIBC_ISO_ONLY */
+#endif /* defined(RT_USING_LIBC) && !__RT_USING_INTERNAL_LIBC_ONLY */
 
 /**@}*/
 

include/rtthread.h

@@ -659,13 +659,12 @@ void rt_components_board_init(void);
 #else
 int rt_kprintf(const char *fmt, ...);
 void rt_kputs(const char *str);
+#endif /* RT_USING_CONSOLE */
 
 rt_err_t rt_backtrace(void);
 rt_err_t rt_backtrace_thread(rt_thread_t thread);
 rt_err_t rt_backtrace_frame(struct rt_hw_backtrace_frame *frame);
 
-#endif /* RT_USING_CONSOLE */
-
 int rt_vsprintf(char *dest, const char *format, va_list arg_ptr);
 int rt_vsnprintf(char *buf, rt_size_t size, const char *fmt, va_list args);
 int rt_sprintf(char *buf, const char *format, ...);