libc++: Print log/error messages on stderr, not stdout

[ed]

Summary

There are a couple of places where libc++ prints log/error messages to stdout on its own. This may of course interfere with the output generated with applications. Log/error messages should be directed to stderr instead.

[mclow.lists]

You missed one in <string> (line 42)

[ed]

In D8135#136153, @mclow.lists wrote:

You missed one in <string> (line 42)

Ah, thanks for noticing. Updated the diff.

include/__debug

 #   include <cstdio>
 #   include <cstddef>
 #   ifndef _LIBCPP_ASSERT
-#      define _LIBCPP_ASSERT(x, m) ((x) ? (void)0 : (_VSTD::printf("%s\n", m), _VSTD::abort()))
+#      define _LIBCPP_ASSERT(x, m) ((x) ? (void)0 : (_VSTD::fprintf(stderr, "%s\n", m), _VSTD::abort()))
 #   endif
 #endif
 

src/exception.cpp

 #endif  // _LIBCPP_NO_EXCEPTIONS
         (*get_terminate())();
         // handler should not return
-        printf("terminate_handler unexpectedly returned\n");
+        fprintf(stderr, "terminate_handler unexpectedly returned\n");
         ::abort();
 #ifndef _LIBCPP_NO_EXCEPTIONS
     }

     catch (...)
     {
         // handler should not throw exception
-        printf("terminate_handler unexpectedly threw an exception\n");
+        fprintf(stderr, "terminate_handler unexpectedly threw an exception\n");
         ::abort();
     }
 #endif  // _LIBCPP_NO_EXCEPTIONS

 #   else
 #       warning uncaught_exception not yet implemented
 #   endif
-    printf("uncaught_exception not yet implemented\n");
+    fprintf(stderr, "uncaught_exception not yet implemented\n");
     ::abort();
 #endif  // __APPLE__
 }

 #   else
 #       warning exception_ptr not yet implemented
 #   endif
-    printf("exception_ptr not yet implemented\n");
+    fprintf(stderr, "exception_ptr not yet implemented\n");
     ::abort();
 #endif
 }

 #   else
 #       warning exception_ptr not yet implemented
 #   endif
-    printf("exception_ptr not yet implemented\n");
+    fprintf(stderr, "exception_ptr not yet implemented\n");
     ::abort();
 #endif
 }

 #   else
 #       warning exception_ptr not yet implemented
 #   endif
-    printf("exception_ptr not yet implemented\n");
+    fprintf(stderr, "exception_ptr not yet implemented\n");
     ::abort();
 #endif
 }

 #   else
 #       warning exception_ptr not yet implemented
 #   endif
-    printf("exception_ptr not yet implemented\n");
+    fprintf(stderr, "exception_ptr not yet implemented\n");
     ::abort();
 #endif
 }

 #   else
 #       warning exception_ptr not yet implemented
 #   endif
-    printf("exception_ptr not yet implemented\n");
+    fprintf(stderr, "exception_ptr not yet implemented\n");
     ::abort();
 #endif
 }