trace2: use system/global config for default trace2 settings

diff --git a/Documentation/technical/api-run-command.txt b/Documentation/technical/api-run-command.txt
index 5d7d7f2d32f58f8682ca5efb2fd98fe7e74247dd..8bf3e37f5375584e5c9f4543523a40377e08686f 100644 (file)
--- a/Documentation/technical/api-run-command.txt
+++ b/Documentation/technical/api-run-command.txt
@@ -13,6 +13,10 @@ produces in the caller in order to process it.
 Functions
 ---------
 
+`child_process_init`::
+
+       Initialize a struct child_process variable.
+
 `start_command`::
 
        Start a sub-process. Takes a pointer to a `struct child_process`
@@ -42,6 +46,13 @@ Functions
        The argument dir corresponds the member .dir. The argument env
        corresponds to the member .env.
 
+`child_process_clear`::
+
+       Release the memory associated with the struct child_process.
+       Most users of the run-command API don't need to call this
+       function explicitly because `start_command` invokes it on
+       failure and `finish_command` calls it automatically already.
+
 The functions above do the following:
 
 . If a system call failed, errno is set and -1 is returned. A diagnostic
@@ -96,8 +107,8 @@ command to run in a sub-process.
 
 The caller:
 
-1. allocates and clears (memset(&chld, 0, sizeof(chld));) a
-   struct child_process variable;
+1. allocates and clears (using child_process_init() or
+   CHILD_PROCESS_INIT) a struct child_process variable;
 2. initializes the members;
 3. calls start_command();
 4. processes the data;
@@ -109,6 +120,13 @@ terminated), of which .argv[0] is the program name to run (usually
 without a path). If the command to run is a git command, set argv[0] to
 the command name without the 'git-' prefix and set .git_cmd = 1.
 
+Note that the ownership of the memory pointed to by .argv stays with the
+caller, but it should survive until `finish_command` completes. If the
+.argv member is NULL, `start_command` will point it at the .args
+`argv_array` (so you may use one or the other, but you must use exactly
+one). The memory in .args will be cleaned up automatically during
+`finish_command` (or during `start_command` when it is unsuccessful).
+
 The members .in, .out, .err are used to redirect stdin, stdout,
 stderr as follows:
 
@@ -158,6 +176,11 @@ string pointers (NULL terminated) in .env:
 . If the string does not contain '=', it names an environment
   variable that will be removed from the child process's environment.
 
+If the .env member is NULL, `start_command` will point it at the
+.env_array `argv_array` (so you may use one or the other, but not both).
+The memory in .env_array will be cleaned up automatically during
+`finish_command` (or during `start_command` when it is unsuccessful).
+
 To specify a new initial working directory for the sub-process,
 specify it in the .dir member.