6 files changed, 56 insertions, 5 deletions

diff --git a/erts/doc/src/erl_nif.xml b/erts/doc/src/erl_nif.xml
index fefec3eeb6..33a4fee182 100644
--- a/erts/doc/src/erl_nif.xml
+++ b/erts/doc/src/erl_nif.xml
@@ -1763,6 +1763,15 @@ enif_map_iterator_destroy(env, &iter);
       <desc><p>Get the byte size of a resource object <c>obj</c> obtained by
       <seealso marker="#enif_alloc_resource">enif_alloc_resource</seealso>.</p></desc>
     </func>
+
+    <func><name><ret>int</ret><nametext>enif_snprintf(char *str, size_t size, const char *format, ...)</nametext></name>
+      <fsummary>Format strings and Erlang terms</fsummary>
+      <desc>
+          <p>Similar to <c>snprintf</c> but this format string also accepts <c>"%T"</c> which formats Erlang terms.
+          </p>
+      </desc>
+    </func>
+
     <func>
       <name><ret>void</ret><nametext>enif_system_info(ErlNifSysInfo *sys_info_ptr, size_t size)</nametext></name>
       <fsummary>Get information about the Erlang runtime system</fsummary>
diff --git a/erts/emulator/beam/erl_nif.c b/erts/emulator/beam/erl_nif.c
index 8a3007d52a..159dc66ad5 100644
--- a/erts/emulator/beam/erl_nif.c
+++ b/erts/emulator/beam/erl_nif.c
@@ -1810,6 +1810,16 @@ int enif_fprintf(void* filep, const char* format, ...)
     return ret;
 }    
 
+int enif_snprintf(char *buffer, size_t size, const char* format, ...) 
+{ 
+    int ret;
+    va_list arglist;
+    va_start(arglist, format);
+    ret = erts_vsnprintf(buffer, size, format, arglist);
+    va_end(arglist);
+    return ret;
+}
+
 /***********************************************************
  **       Memory managed (GC'ed) "resource" objects       **
  ***********************************************************/
diff --git a/erts/emulator/beam/erl_nif.h b/erts/emulator/beam/erl_nif.h
index 02c82415fd..da7a754757 100644
--- a/erts/emulator/beam/erl_nif.h
+++ b/erts/emulator/beam/erl_nif.h
@@ -49,9 +49,10 @@
 ** 2.8: 18.0 add enif_has_pending_exception
 ** 2.9: 18.2 enif_getenv
 ** 2.10: Time API
+** 2.11: 19.0 enif_snprintf
 */
 #define ERL_NIF_MAJOR_VERSION 2
-#define ERL_NIF_MINOR_VERSION 10
+#define ERL_NIF_MINOR_VERSION 11
 
 /*
  * The emulator will refuse to load a nif-lib with a major version
diff --git a/erts/emulator/beam/erl_nif_api_funcs.h b/erts/emulator/beam/erl_nif_api_funcs.h
index 1bdac51d1f..b211ab4b16 100644
--- a/erts/emulator/beam/erl_nif_api_funcs.h
+++ b/erts/emulator/beam/erl_nif_api_funcs.h
@@ -174,6 +174,7 @@ ERL_NIF_API_FUNC_DECL(int, enif_term_to_binary, (ErlNifEnv *env, ERL_NIF_TERM te
 ERL_NIF_API_FUNC_DECL(size_t, enif_binary_to_term, (ErlNifEnv *env, const unsigned char* data, size_t sz, ERL_NIF_TERM *term, unsigned int opts));
 ERL_NIF_API_FUNC_DECL(int, enif_port_command, (ErlNifEnv *env, const ErlNifPort* to_port, ErlNifEnv *msg_env, ERL_NIF_TERM msg));
 ERL_NIF_API_FUNC_DECL(int,enif_is_on_dirty_scheduler,(ErlNifEnv*));
+ERL_NIF_API_FUNC_DECL(int,enif_snprintf,(char * buffer, size_t size, const char *format, ...));
 
 /*
 ** ADD NEW ENTRIES HERE (before this comment) !!!
@@ -330,6 +331,7 @@ ERL_NIF_API_FUNC_DECL(int,enif_is_on_dirty_scheduler,(ErlNifEnv*));
 #  define enif_binary_to_term ERL_NIF_API_FUNC_MACRO(enif_binary_to_term)
 #  define enif_port_command ERL_NIF_API_FUNC_MACRO(enif_port_command)
 #  define enif_is_on_dirty_scheduler ERL_NIF_API_FUNC_MACRO(enif_is_on_dirty_scheduler)
+#  define enif_snprintf ERL_NIF_API_FUNC_MACRO(enif_snprintf)
 
 /*
 ** ADD NEW ENTRIES HERE (before this comment)
diff --git a/erts/emulator/test/nif_SUITE.erl b/erts/emulator/test/nif_SUITE.erl
index a1e1495480..a0e9f1bad6 100644
--- a/erts/emulator/test/nif_SUITE.erl
+++ b/erts/emulator/test/nif_SUITE.erl
@@ -45,7 +45,8 @@
          nif_now_time/1, nif_cpu_time/1, nif_unique_integer/1,
          nif_is_process_alive/1, nif_is_port_alive/1,
          nif_term_to_binary/1, nif_binary_to_term/1,
-         nif_port_command/1
+         nif_port_command/1,
+         nif_snprintf/1
 	]).
 
 -export([many_args_100/100]).
@@ -79,8 +80,8 @@ all() ->
      nif_now_time, nif_cpu_time, nif_unique_integer,
      nif_is_process_alive, nif_is_port_alive,
      nif_term_to_binary, nif_binary_to_term,
-     nif_port_command
-    ].
+     nif_port_command,
+     nif_snprintf].
 
 init_per_testcase(_Case, Config) ->
     Config.
@@ -1952,9 +1953,18 @@ nif_port_command(Config) ->
     port_close(Port),
 
     {'EXIT', {badarg, _}} = (catch port_command_nif(Port, "hello\n")),
+    ok.
 
+nif_snprintf(Config) ->
+    ensure_lib_loaded(Config),
+    <<"ok",0>> = format_term_nif(3,ok),
+    <<"o",0>>  = format_term_nif(2,ok),
+    <<"\"hello world\"",0>> = format_term_nif(14,"hello world"),
+    <<"{{hello,world,-33},3.14",_/binary>> = format_term_nif(50,{{hello,world, -33}, 3.14, self()}),
+    <<"{{hello,world,-33},",0>> = format_term_nif(20,{{hello,world, -33}, 3.14, self()}),
     ok.
 
+
 %% The NIFs:
 lib_version() -> undefined.
 call_history() -> ?nif_stub.
@@ -2015,6 +2025,7 @@ is_port_alive_nif(_) -> ?nif_stub.
 term_to_binary_nif(_, _) -> ?nif_stub.
 binary_to_term_nif(_, _, _) -> ?nif_stub.
 port_command_nif(_, _) -> ?nif_stub.
+format_term_nif(_,_) -> ?nif_stub.
 
 %% maps
 is_map_nif(_) -> ?nif_stub.
diff --git a/erts/emulator/test/nif_SUITE_data/nif_SUITE.c b/erts/emulator/test/nif_SUITE_data/nif_SUITE.c
index 73073ad59f..13846244d4 100644
--- a/erts/emulator/test/nif_SUITE_data/nif_SUITE.c
+++ b/erts/emulator/test/nif_SUITE_data/nif_SUITE.c
@@ -1998,6 +1998,23 @@ static ERL_NIF_TERM port_command(ErlNifEnv* env, int argc, const ERL_NIF_TERM ar
     return atom_true;
 }
 
+static ERL_NIF_TERM format_term(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
+{
+    ErlNifBinary obin;
+    unsigned int size;
+
+    if (!enif_get_uint(env, argv[0], &size))
+	return enif_make_badarg(env);
+    if (!enif_alloc_binary(size,&obin))
+	return enif_make_badarg(env);
+
+    if (enif_snprintf((char*)obin.data, (size_t)size, "%T", argv[1]) < 0)
+        return atom_false;
+
+    return enif_make_binary(env,&obin);
+}
+
+
 static ErlNifFunc nif_funcs[] =
 {
     {"lib_version", 0, lib_version},
@@ -2073,7 +2090,8 @@ static ErlNifFunc nif_funcs[] =
     {"is_port_alive_nif", 1, is_port_alive},
     {"term_to_binary_nif", 2, term_to_binary},
     {"binary_to_term_nif", 3, binary_to_term},
-    {"port_command_nif", 2, port_command}
+    {"port_command_nif", 2, port_command},
+    {"format_term_nif", 2, format_term}
 };
 
 ERL_NIF_INIT(nif_SUITE,nif_funcs,load,reload,upgrade,unload)