ltrace(1)						ltrace(1)


NAME
       ltrace - A library call tracer

SYNOPSIS
       ltrace  [-dfiLSrtttChV] [-a column] [-s strsize] [-o file-
       name] [-u username]  [-p	 pid]  ...  [-e	 expr]	[--debug]
       [--demangle] [--align=column] [--output=filename] [--help]
       [--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
       -d, --debug
	      Increase the debugging level.

       -f     Trace  child  processes as they are created by cur-
	      rently  traced processes as a result of the fork(2)
	      or  clone(2)  system  calls.   The  new  process is
	      attached as soon as its pid is known.

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

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

       -S     Display system calls as well as library calls

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

       -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.

       -C, --demangle
	      Decode (demangle) low-level symbol names into user-
	      level  names.   Besides removing any initial under-
	      score prepended by the system, this makes C++ func-
	      tion names readable.

       -a, --align column
	      Align  return  values  in a secific column (default
	      column 50).

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

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

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

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

       -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.

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

       -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/i386, Linux/m68k, and Linux/arm

       Only ELF32 binaries are supported

       If you like to report a bug, send a notice to the  author,
       or  use	the  bug(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)

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