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-rw-r--r--Documentation/technical/api-parse-options.txt7
-rw-r--r--Documentation/technical/api-trace.txt45
2 files changed, 51 insertions, 1 deletions
diff --git a/Documentation/technical/api-parse-options.txt b/Documentation/technical/api-parse-options.txt
index 5f0757dcc9..695bd4bf43 100644
--- a/Documentation/technical/api-parse-options.txt
+++ b/Documentation/technical/api-parse-options.txt
@@ -231,6 +231,13 @@ There are some macros to easily define options:
pass the command-line option, which can be specified multiple times,
to another command.
+`OPT_CMDMODE(short, long, &int_var, description, enum_val)`::
+ Define an "operation mode" option, only one of which in the same
+ group of "operating mode" options that share the same `int_var`
+ can be given by the user. `enum_val` is set to `int_var` when the
+ option is used, but an error is reported if other "operating mode"
+ option has already set its value to the same `int_var`.
+
The last element of the array must be `OPT_END()`.
diff --git a/Documentation/technical/api-trace.txt b/Documentation/technical/api-trace.txt
index 097a651d96..fadb5979c4 100644
--- a/Documentation/technical/api-trace.txt
+++ b/Documentation/technical/api-trace.txt
@@ -28,7 +28,7 @@ static struct trace_key trace_foo = TRACE_KEY_INIT(FOO);
static void trace_print_foo(const char *message)
{
- trace_print_key(&trace_foo, message);
+ trace_printf_key(&trace_foo, "%s", message);
}
------------
+
@@ -95,3 +95,46 @@ for (;;) {
}
trace_performance(t, "frotz");
------------
+
+Bugs & Caveats
+--------------
+
+GIT_TRACE_* environment variables can be used to tell Git to show
+trace output to its standard error stream. Git can often spawn a pager
+internally to run its subcommand and send its standard output and
+standard error to it.
+
+Because GIT_TRACE_PERFORMANCE trace is generated only at the very end
+of the program with atexit(), which happens after the pager exits, it
+would not work well if you send its log to the standard error output
+and let Git spawn the pager at the same time.
+
+As a work around, you can for example use '--no-pager', or set
+GIT_TRACE_PERFORMANCE to another file descriptor which is redirected
+to stderr, or set GIT_TRACE_PERFORMANCE to a file specified by its
+absolute path.
+
+For example instead of the following command which by default may not
+print any performance information:
+
+------------
+GIT_TRACE_PERFORMANCE=2 git log -1
+------------
+
+you may want to use:
+
+------------
+GIT_TRACE_PERFORMANCE=2 git --no-pager log -1
+------------
+
+or:
+
+------------
+GIT_TRACE_PERFORMANCE=3 3>&2 git log -1
+------------
+
+or:
+
+------------
+GIT_TRACE_PERFORMANCE=/path/to/log/file git log -1
+------------