How to use ltrace with wildcards

Question

I'm new to ltrace.

• I'd like to use wildcards (patterns) to trace function calls, but they don't seem to work as they should, based on the web pages I see, e.g. http://man7.org/linux/man-pages/man1/ltrace.1.html

E.g. this works:

ltrace -c -e "XDrawLine" -p 10876 ^C
% time     seconds  usecs/call     calls      function
------ ----------- ----------- --------- --------------------
100.00    4.925592         501      9829 XDrawLine
------ ----------- ----------- --------- --------------------
100.00    4.925592                  9829 total

But this matches nothing:

trace -c -e "XDrawLin*" -p 10876
^C
% time     seconds  usecs/call     calls      function
------ ----------- ----------- --------- --------------------
------ ----------- ----------- --------- --------------------
100.00    0.000000                     0 total

Also, no luck with -e "/XDrawLin.*/" or -e "XDrawLin.*" either. Any working example is appreciated.

• If this is sorted out, I'd like to move on to how to trace on C++ lib symbols, shall I use mangled or demangled format ?

Answer 1

The functionality of the -e switch evolved over ltrace releases. Even fairly recent Linux releases frequently shipped an older ltrace, and that’s most likely is the issue for you. (For example, RHEL6 if I remember correctly, ships with version 0.5.) Run ltrace --v and make sure you have version 0.7 and above.

* Version 0.7.0 [2012-11-09 Fri]

** Tracing
...

*** Limited support for tracing returns from tail call functions

*** -e, -x and -l selectors now allow using globs and regular expressions

http://anonscm.debian.org/gitweb/?p=collab-maint/ltrace.git;a=blob_plain;f=NEWS;hb=0.7.3

If you have an older ltrace - update it with your package manager or download it from http://freecode.com/projects/ltrace