xref: /openbsd/lib/libc/gmon/moncontrol.3 (revision 404b540a)
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30.Dd $Mdocdate: May 31 2007 $
31.Dt MONCONTROL 3
32.Os
33.Sh NAME
34.Nm moncontrol ,
35.Nm monstartup
36.Nd control execution profile
37.Sh SYNOPSIS
38.Fn moncontrol "int mode"
39.Fn monstartup "u_long *lowpc" "u_long *highpc"
40.Sh DESCRIPTION
41An executable program compiled using the
42.Fl pg
43option to
44.Xr cc 1
45automatically includes calls to collect statistics for the
46.Xr gprof 1
47call-graph execution profiler.
48In typical operation, profiling begins at program startup
49and ends when the program calls exit.
50When the program exits, the profiling data are written to the file
51.Em gmon.out ,
52then
53.Xr gprof 1
54can be used to examine the results.
55.Pp
56.Fn moncontrol
57selectively controls profiling within a program.
58When the program starts, profiling begins.
59To stop the collection of histogram ticks and call counts use
60.Fn moncontrol 0 ;
61to resume the collection of histogram ticks and call counts use
62.Fn moncontrol 1 .
63This feature allows the cost of particular operations to be measured.
64Note that an output file will be produced on program exit
65regardless of the state of
66.Fn moncontrol .
67.Pp
68Programs that are not loaded with
69.Fl pg
70may selectively collect profiling statistics by calling
71.Fn monstartup
72with the range of addresses to be profiled.
73.Fa lowpc
74and
75.Fa highpc
76specify the address range that is to be sampled;
77the lowest address sampled is that of
78.Fa lowpc
79and the highest is just below
80.Fa highpc .
81Only functions in that range that have been compiled with the
82.Fl pg
83option to
84.Xr cc 1
85will appear in the call graph part of the output;
86however, all functions in that address range will
87have their execution time measured.
88Profiling begins on return from
89.Fn monstartup .
90.Sh FILES
91.Bl -tag -width Pa -compact
92.It Pa gmon.out	execution data file
93.El
94.Sh SEE ALSO
95.Xr cc 1 ,
96.Xr gprof 1 ,
97.Xr profil 2
98