[libc] implement extension standard C functions (#6044)

* implement extension standard C functions

1 files changed, 43 insertions, 0 deletions

diff --git a/components/libc/compilers/common/include/posix/string.h b/components/libc/compilers/common/include/posix/string.h
new file mode 100644
index 0000000000..475de513fc
--- /dev/null
+++ b/components/libc/compilers/common/include/posix/string.h
@@ -0,0 +1,43 @@
+/*
+ * Copyright (c) 2006-2022, RT-Thread Development Team
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Change Logs:
+ * Date           Author       Notes
+ * 2022-01-12     Meco Man     The first version.
+ */
+
+#ifndef __POSIX_STRING_H__
+#define __POSIX_STRING_H__
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stddef.h>
+#include <string.h>
+
+void bzero(void * s, size_t n);
+void bcopy(const void * src, void * dest, size_t n);
+int bcmp(const void * s1, const void * s2, size_t n);
+void explicit_bzero(void * s, size_t n);
+char *index(const char * s, int c);
+char *rindex(const char * s, int c);
+int ffs(int i);
+int ffsl(long i);
+int ffsll(long long i);
+void *memrchr(const void* ptr, int ch, size_t pos);
+size_t strnlen(const char *s, size_t maxlen);
+char* strchrnul(const char *s, int c);
+int strcasecmp(const char * s1, const char * s2);
+int strncasecmp(const char * s1, const char * s2, size_t n);
+char *strdup(const char *s);
+char *strndup(const char *s, size_t size);
+char *strtok_r(char *str, const char *delim, char **saveptr);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __POSIX_STRING_H__ */