Fix the retrieval of the new SYSTEMNAME variable. Also, clarify some

documentation of how pbx_retrieve_variable works. (issue #6493)

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@10209 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/pbx.c b/pbx.c
index 04f9a312a5a41109cb7f141ae8bdc082480bcddf..b9f4a7a3481915b9ccaf0044ca90f0eafbc79cfe 100644 (file)
--- a/pbx.c
+++ b/pbx.c
@@ -909,13 +909,18 @@ void pbx_retrieve_variable(struct ast_channel *c, const char *var, char **ret, c
 
        /*
         * Look first into predefined variables, then into variable lists.
+        * Variable 's' points to the result, according to the following rules:
         * s == &not_found (set at the beginning) means that we did not find a
-        * matching variable and need to look into more places.
+        *      matching variable and need to look into more places.
         * If s != &not_found, s is a valid result string as follows:
         * s = NULL if the variable does not have a value;
+        *      you typically do this when looking for an unset predefined variable.
         * s = workspace if the result has been assembled there;
+        *      typically done when the result is built e.g. with an snprintf(),
+        *      so we don't need to do an additional copy.
         * s != workspace in case we have a string, that needs to be copied
         *      (the ast_copy_string is done once for all at the end).
+        *      Typically done when the result is already available in some string.
         */
        s = &not_found; /* default value */
        if (c) {        /* This group requires a valid channel */
@@ -961,7 +966,7 @@ void pbx_retrieve_variable(struct ast_channel *c, const char *var, char **ret, c
                        snprintf(workspace, workspacelen, "%u",(int)time(NULL));
                        s = workspace;
                } else if (!strcmp(var, "SYSTEMNAME")) {
-                       ast_copy_string(workspace, ast_config_AST_SYSTEM_NAME, workspacelen);
+                       s = ast_config_AST_SYSTEM_NAME;
                }
        }
        /* if not found, look into chanvars or global vars */