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DTRACE(1)                   General Commands Manual                  DTRACE(1)

NAME
       dtrace  -  Dtrace  compatible  user application static probe generation
       tool.

SYNOPSIS
       dtrace -s file [OPTIONS]

DESCRIPTION
       The dtrace command converts probe descriptions defined in file.d into a
       probe header file via the -h option or a probe description file via the
       -G option.

OPTIONS
       -h     generate a systemtap header file.

       -G     generate a systemtap probe definition object file.

       -o file
              is the name of the output file.  If the -G option is given  then
              the output file will be called file.o; if the -h option is given
              then the output file will be called file.h.

       -C     run the cpp preprocessor on the input file when the -h option is
              given.

       -I file
              give this include path to cpp when the -C option is given.

       -k     keep  temporary files, for example the C language source for the
              -G option.

EXAMPLES
       Systemtap is source compatible  with  dtrace  user  application  static
       probe support.  Given a file test.d containing:
              provider sdt_probes
              {
                probe test_0 (int type);
                probe test_1 (struct astruct node);
              };
              struct astruct {int a; int b;};
       Then the command "dtrace -s test.d -G" will create the probe definition
       file test.o and the command "dtrace -stest.d -h" will create the  probe
       header  file  test.h Subsequently the application can use the generated
       macros this way:
              #include "test.h"
               ...
              struct astruct s;
               ...
              SDT_PROBES_TEST_0(value);
               ...
              if (SDT_PROBES_TEST_1_ENABLED())
                  SDT_PROBES_TEST_1(expensive_function(s));

SEMAPHORES
       Semaphores are flag variables used by probes as a way of bypassing  po-
       tentially  costly  processing  to prepare arguments for probes that may
       not even be active.  They are automatically  set/cleared  by  systemtap
       when  a  relevant script is running, so the argument setup cost is only
       paid when necessary.  These semaphore variables are defined within  the
       the "test.o" object file, which must therefore be linked into an appli-
       cation.
       Sometimes, semaphore variables are not necessary nor helpful.  Skipping
       them  can  simplify  the  build process, by omitting the extra "test.o"
       file.   To  skip   dependence   upon   semaphore   variables,   include
       "<sys/sdt.h>" within the application before "test.h":
              #include <sys/sdt.h>
              #include "test.h"
               ...
              struct astruct s;
               ...
              SDT_PROBES_TEST_0(value);
               ...
              if (SDT_PROBES_TEST_1_ENABLED())
                 SDT_PROBES_TEST_1(cheap_function(s));
       In this mode, the ENABLED() test is fixed at 1.

SEE ALSO
       stap(1),
       stappaths(7)

BUGS
       Use  the  Bugzilla  link  of  the project web page or our mailing list.
       http://sourceware.org/systemtap/, <systemtap AT sourceware.org>.
       error::reporting(7stap),
       https://sourceware.org/systemtap/wiki/HowToReportBugs

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