From 3bd1b51d3a3884df186beddaf3a101a5e624f07a Mon Sep 17 00:00:00 2001 From: Christian Couder Date: Mon, 7 Mar 2016 11:38:53 +0100 Subject: Documentation: talk about pager in api-trace.txt Signed-off-by: Christian Couder Signed-off-by: Junio C Hamano diff --git a/Documentation/technical/api-trace.txt b/Documentation/technical/api-trace.txt index 097a651..389ae16 100644 --- a/Documentation/technical/api-trace.txt +++ b/Documentation/technical/api-trace.txt @@ -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 +------------ -- cgit v0.10.2-6-g49f6