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MONCONTROL(3)          FreeBSD Library Functions Manual          MONCONTROL(3)

     moncontrol, monstartup - control execution profile

     Standard C Library (libc, -lc)

     #include <sys/types.h>
     #include <sys/gmon.h>

     moncontrol(int mode);

     monstartup(u_long lowpc, u_long highpc);

     An executable program compiled using the -pg option to cc(1)
     automatically includes calls to collect statistics for the gprof(1) call-
     graph execution profiler.  In typical operation, profiling begins at
     program startup and ends when the program calls exit.  When the program
     exits, the profiling data are written to the file progname.gmon, where
     progname is the name of the program, then gprof(1) can be used to examine
     the results.

     The moncontrol() function selectively controls profiling within a
     program.  When the program starts, profiling begins.  To stop the
     collection of histogram ticks and call counts use moncontrol(0); to
     resume the collection of histogram ticks and call counts use
     moncontrol(1).  This feature allows the cost of particular operations to
     be measured.  Note that an output file will be produced on program exit
     regardless of the state of moncontrol().

     Programs that are not loaded with -pg may selectively collect profiling
     statistics by calling monstartup() with the range of addresses to be
     profiled.  The lowpc and highpc arguments specify the address range that
     is to be sampled; the lowest address sampled is that of lowpc and the
     highest is just below highpc.  Only functions in that range that have
     been compiled with the -pg option to cc(1) will appear in the call graph
     part of the output; however, all functions in that address range will
     have their execution time measured.  Profiling begins on return from

     The following environment variables affect the execution of moncontrol:

     PROFIL_USE_PID      If set, the pid of the process is inserted into the

     progname.gmon  execution data file

     cc(1), gprof(1), profil(2), clocks(7)

FreeBSD 11.1-RELEASE-p4          June 14, 2004         FreeBSD 11.1-RELEASE-p4
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