.TH CALLS 1
.SH NAME
calls \- print static call graph of a C program
.SH SYNOPSIS
.B calls
[
.B \-ptv
] [
.B \-f
.I function
] [
.B \-w
.I width
\&...
] [
.B \-D
.I def
] [
.B \-U
.I def
] [
.B \-I
.I dir
] [
file ...
]
.SH DESCRIPTION
.I Calls
reads
.IR file s,
which should be the source of C programs,
and writes the analysed calling pattern to standard output.
If no file names are given,
standard input will be read.
.I Calls
is intended to help analyse the flow of a program by laying out the
functions called in the hierarchical manner used in
.I "Software Tools"
by
B. Kernighan and P. Plauger.
.PP
All input is first filtered through
.IR cpp (1).
Functions called but not defined within the source
.IR file s
are shown as:
.PP
.RS
function
.B [external]
.RE
.PP
Recursive references are shown as:
.PP
.RS
.B <<<
function
.RE
.PP
Options are:
.TP 0.6i
.B \-f
Add
.I function
as a root of a call graph to be printed.
.TP
.B -p
Make
.I cpp
search the APE
.I include
directories.
.TP
.B \-t
Provides a terse form of output,
in which the calling pattern for any
function is printed only once on the first occurrence of the function.
Subsequent occurrences output the function name and a notation
.IP "" 1i
\&...
.BI "[see line " xx ]
.IP "" 0.6i
This is the default case.
.TP 0.6i
.B \-v
Full output of function calling patterns on every occurrence.
.TP
.BI \-w n
Set the output width to
.IR n .
The default is 80 columns.
.TP
.BI \-D name
.PD 0
.TP
.PD 0.4v
.BI \-D name=defn
Define the
.I name
for
.IR cpp ,
as if by
.BR #define .
If no definition is given, the name is defined as 1.
.TP
.BI \-U name
Remove any initial definition of
.IR name ,
where
.I name
is a reserved symbol that is predefined by
.IR cpp .
.TP
.BI \-I dir
Change the algorithm for searching for
.B #include
files whose names do not begin with
.B /
to look in
.I dir
before looking in the directories on the standard list.
.SH EXAMPLES
What does
.I cat
call?
.IP
.EX
% calls -f main /sys/src/cmd/cat.c
1   main
2       cat
3               read [external]
4               write [external]
5               sysfatal [external]
6       open [external]
7       sysfatal [external]
8       close [external]
9       exits [external]
.EE
.br
.ne 7
.PP
What internal functions does
.I dd
call?
.IP
.EX
% calls -f main /sys/src/cmd/dd.c | grep -v '\e[external\e]'
1   main
5       number
6               <<< number
9       match
17      flsh
21              term
22                      stats
25      term ... [see line 21]
26      stats ... [see line 22]
.EE
.PP
Note the recursion in
.IR number .
.PP
Generate the PC kernel's internal call graph.
.IP
.EX
cd /sys/src/9/pc
calls -f main -I../port -I. ../port/*.c ../ip/*.c *.c |
	grep -v external
.EE
.SH BUGS
Forward declared functions defined within a function body which are not
subsequently used within that function body will be listed as having been
called.
.PP
Does not understand calls through function pointers.
.PP
Does not understand the restricted scope of
.I static
functions.