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Linux 2.6 - man page for ltrace (linux section 1)

ltrace(1)										ltrace(1)

NAME
       ltrace - A library call tracer

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] [--demangle] [--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 executed 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 system, this makes C++ function names
	      readable.

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

	      01     DEBUG_GENERAL.  Shows helpful progress information

	      010    DEBUG_EVENT.  Shows every event received by a traced program

	      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:
	      [!]value1[,value2]...
	      where the values are the functions to trace.  Using an exclamation mark negates the
	      set  of values.  For example -e printf means to trace only the printf library call.
	      By contrast, -e !printf means to trace every library call except printf.

	      Note that some shells use the exclamation point for history expansion; even  inside
	      quoted arguments.  If so, you must escape the exclamation point with a backslash.

       -f     Trace child processes as they are created by currently traced processes as a result
	      of the fork(2) or clone(2) system calls.	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 dif-
	      ference 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.

       -X extern
	      Some  architectures  need  to know where to set a breakpoint that will be hit after
	      the dynamic linker has run.  If this flag is used, then the breakpoint  is  set  at
	      extern,  which  must be an external function.  By default, '_start' is used.  NOTE:
	      this flag is only available on the architectures that need it.

       -x extern
	      Trace the external function extern.  This option may be repeated.

       -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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