ltrace



SYNOPSIS
       ltrace [-CfhiLrStttV] [-a column] [-A maxelts] [-D level] [-e expr] [-l
       filename] [-n nr] [-o filename] [-p pid] ... [-s strsize] [-u username]
       [-X  extern] [-x extern] ... [--align=column] [--debug=level] [--deman-
       gle] [--help]  [--indent=nr]  [--library=filename]  [--output=filename]
       [--version] [command [arg ...]]


DESCRIPTION
       ltrace  is  a  program  that simply runs the specified command until it
       exits.  It intercepts and records the dynamic library calls  which  are
       called  by  the  executed process and the signals which are received by
       that process.  It can also intercept and print the  system  calls  exe-
       cuted by the program.

       Its use is very similar to strace(1).


OPTIONS
       -a, --align column
              Align  return values in a specific column (default column is 5/8
              of screen width).

       -A maxelts
              Maximum number of array elements to print before suppressing the
              rest with an ellipsis ("...")

       -c     Count  time and calls for each library call and report a summary
              on program exit.

       -C, --demangle
              Decode (demangle) low-level symbol names into user-level  names.
              Besides  removing any initial underscore prefix used by the sys-
              tem, this makes C++ function names readable.

       -D, --debug level
              Show debugging output of ltrace itself.  level must be a sum  of
              some of the following numbers:

              01     DEBUG_GENERAL.  Shows helpful progress information

              010    DEBUG_EVENT.  Shows every event received by a traced pro-
                     gram

              020    DEBUG_PROCESS.  Shows every action ltrace carries upon  a
                     traced process

              040    DEBUG_FUNCTION.  Shows every entry to internal functions

       -e expr
              A  qualifying  expression  which modifies which events to trace.
              The format of the expression is:
              The new process is attached immediately.

       -F     Load  an  alternate  config file. Normally, /etc/ltrace.conf and
              ~/.ltrace.conf will be read (the latter only if it exists).  Use
              this option to load the given file or files instead of those two
              default files.

       -h, --help
              Show a summary of the options to ltrace and exit.

       -i     Print the instruction pointer at the time of the library call.

       -l, --library filename
              Display only the symbols included in the library  filename.   Up
              to  30  library names can be specified with several instances of
              this option.

       -L     DON'T display library calls (use it with the -S option).

       -n, --indent nr
              Indent trace output by nr number of spaces for each  new  nested
              call.  Using  this  option  makes the program flow visualization
              easy to follow.

       -o, --output filename
              Write the trace output to  the  file  filename  rather  than  to
              stderr.

       -p pid Attach to the process with the process ID pid and begin tracing.

       -r     Print  a  relative  timestamp with each line of the trace.  This
              records the time difference between the beginning of  successive
              lines.

       -s strsize
              Specify the maximum string size to print (the default is 32).

       -S     Display system calls as well as library calls

       -t     Prefix each line of the trace with the time of day.

       -tt    If given twice, the time printed will include the microseconds.

       -ttt   If  given thrice, the time printed will include the microseconds
              and the leading portion will be printed as the number of seconds
              since the epoch.

       -T     Show   the   time  spent inside each call. This records the time
              difference between the beginning and the end of each call.

       -u username
              Run command with the userid, groupid and supplementary groups of
              username.   This  option is only useful when running as root and
              enables the correct execution of setuid and/or setgid binaries.

       -V, --version
              Show the version number of ltrace and exit.


BUGS
       It has most of the bugs stated in strace(1).

       Manual page and documentation are not very up-to-date.

       Option -f sometimes fails to trace some children.

       It only works on Linux and in a small subset of architectures.

       Only ELF32 binaries are supported.

       Calls to dlopen()ed libraries will not be traced.

       If  you  would like to report a bug, send a message to the mailing list
       (ltrace-devel@lists.alioth.debian.org), or use the reportbug(1) program
       if you are under the Debian GNU/Linux distribution.


FILES
       /etc/ltrace.conf
              System configuration file

       ~/.ltrace.conf
              Personal config file, overrides /etc/ltrace.conf


AUTHOR
       Juan Cespedes <cespedes@debian.org>


SEE ALSO
       strace(1), ptrace(2)




                                                                     ltrace(1)
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