diff --git a/m-core.h b/m-core.h
index 3584a3f2..52658637 100644
--- a/m-core.h
+++ b/m-core.h
@@ -29,7 +29,6 @@
 #include <stdbool.h>
 #include <stdint.h>
 #include <limits.h>
-#include <stdarg.h>
 #include <string.h>
 #include <ctype.h>
 #include <stdlib.h>
@@ -44,6 +43,15 @@
 # include <stdio.h>
 #endif
 
+/* By default, always use stdarg. Can be turned off in specific environement if needed
+   by defining M_USE_STDARG to 0 */
+#ifndef M_USE_STDARG
+# define M_USE_STDARG 1
+#endif
+#if M_USE_STDARG
+# include <stdarg.h>
+#endif
+
 
 /***************************************************************/
 /************************ Compiler Macro ***********************/
@@ -2054,6 +2062,8 @@ M_PARSE_DEFAULT_TYPE_DEF(m_core_parse_ldouble, long double, strtold, )
 #endif
 
 
+#if M_USE_STDARG
+
 /* Define the allocation of the temporary string used by M_CSTR
    Default is 256 bytes (so 255 characters excluding the final null char).
    It can be overriden by users if needed.
@@ -2123,6 +2133,8 @@ m_core_snprintf(char *str, size_t size, const char *format, ...)
 
 #endif
 
+#endif // Have stdarg
+
 
 /************************************************************/
 /********************* HASH selection ***********************/
diff --git a/m-string.h b/m-string.h
index 4a0b226f..19ac40d5 100644
--- a/m-string.h
+++ b/m-string.h
@@ -26,11 +26,6 @@
 #ifndef MSTARLIB_STRING_H
 #define MSTARLIB_STRING_H
 
-#include <ctype.h>
-#include <stdio.h>
-#include <stdarg.h>
-#include <string.h>
-
 #include "m-core.h"
 
 M_BEGIN_PROTECTED_CODE
@@ -909,6 +904,8 @@ string_replace_all (string_t v, const string_t str1, const string_t str2)
   }
 }
 
+#if M_USE_STDARG
+
 /* Format in the string the given printf format */
 static inline int
 string_vprintf (string_t v, const char format[], va_list args)
@@ -989,6 +986,10 @@ string_cat_printf (string_t v, const char format[], ...)
   return size;
 }
 
+#endif // Have stdarg
+
+#if M_USE_STDIO
+
 /* Get a line/pureline/file from the FILE and store it in the string */
 static inline bool
 string_fgets(string_t v, FILE *f, string_fgets_t arg)
@@ -1099,6 +1100,8 @@ string_fputs(FILE *f, const string_t v)
   return fputs(string_get_cstr(v), f) >= 0;
 }
 
+#endif // Have stdio
+
 /* Test if the string starts with the given C string */
 static inline bool
 string_start_with_str_p(const string_t v, const char str[])
@@ -1260,6 +1263,8 @@ string_get_str(string_t v, const string_t v2, bool append)
   STRINGI_CONTRACT (v);
 }
 
+#if M_USE_STDIO
+
 /* Transform the string 'v2' into a formatted string
    and output it in the given FILE */
 static inline void
@@ -1343,6 +1348,8 @@ string_in_str(string_t v, FILE *f)
   return c == '"';
 }
 
+#endif // Have stdio
+
 /* Read the formatted string from the C string
    and set the converted value in the string 'v'.
    Return true in case of success