ltrace(1)						      General Commands Manual							 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 user-
       name] [-X extern] [-x extern] ... [--align=column] [--debug=level] [--demangle] [--help] [--indent=nr] [--library=filename] [--output=file-
       name] [--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 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 following numbers:

	      0x10   DEBUG_EVENT.  Shows every event received by a traced program

	      0x20   DEBUG_PROCESS.  Shows every action ltrace carries upon a traced program

       -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 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.

       -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)  pro-
       gram 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)