3 files changed, 25 insertions, 0 deletions
diff --git a/erts/emulator/beam/bif.tab b/erts/emulator/beam/bif.tab
index dc8e9101de..6037c08dd8 100644
--- a/erts/emulator/beam/bif.tab
+++ b/erts/emulator/beam/bif.tab
@@ -572,6 +572,7 @@ bif erlang:float_to_binary/2
 bif erlang:binary_to_float/1
 
 bif io:printable_range/0
+bif os:unsetenv/1
 
 #
 # Obsolete
diff --git a/erts/emulator/beam/erl_bif_os.c b/erts/emulator/beam/erl_bif_os.c
index 1062d4379b..e07c622928 100644
--- a/erts/emulator/beam/erl_bif_os.c
+++ b/erts/emulator/beam/erl_bif_os.c
@@ -180,3 +180,25 @@ BIF_RETTYPE os_putenv_2(BIF_ALIST_2)
     BIF_RET(am_true);
 }
 
+BIF_RETTYPE os_unsetenv_1(BIF_ALIST_1)
+{
+    char *key_buf;
+    char buf[STATIC_BUF_SIZE];
+
+    key_buf = erts_convert_filename_to_native(BIF_ARG_1,buf,STATIC_BUF_SIZE,
+					      ERTS_ALC_T_TMP,0,0,NULL);
+    if (!key_buf) {
+	BIF_ERROR(BIF_P, BADARG);
+    }
+
+    if (erts_sys_unsetenv(key_buf)) {
+	if (key_buf != buf) {
+	    erts_free(ERTS_ALC_T_TMP, key_buf);
+	}
+	BIF_ERROR(BIF_P, BADARG);
+    }
+    if (key_buf != buf) {
+	erts_free(ERTS_ALC_T_TMP, key_buf);
+    }
+    BIF_RET(am_true);
+}
diff --git a/erts/emulator/beam/sys.h b/erts/emulator/beam/sys.h
index 9561c0be96..d22f125945 100644
--- a/erts/emulator/beam/sys.h
+++ b/erts/emulator/beam/sys.h
@@ -750,6 +750,8 @@ int erts_sys_getenv(char *key, char *value, size_t *size);
 int erts_sys_getenv_raw(char *key, char *value, size_t *size);
 /* erts_sys_getenv__() is only allowed to be used in early init phase */
 int erts_sys_getenv__(char *key, char *value, size_t *size);
+/* erst_sys_unsetenv() returns 0 on success and a value != 0 on failure. */
+int erts_sys_unsetenv(char *key);
 
 /* Easier to use, but not as efficient, environment functions */
 char *erts_read_env(char *key);