I want to visualize the relationship between function calls as an analysis of past software.

#!/bin/bash
while read file; docflow${file}; done | sed'
s/\t/g
US>s /)/)\t/
' |awk-F'\t' '
US>BEGIN{
        ## DELIMITER="->"
        DELIMITER=", "
}
{
        num = NF;
        for (no=1; no<=num;no++) {
                if($no!=""){
                        if(!match($no, "^<")}
                                ga[no] = $no
                        }
                        else{
                                if(match($no, "recursive:")}
                                        ga[no-1] = ga[no-1]"*";
                                }
                                delete ga [ no ];
                                num - = 1;
                        }
                }
        }
        dlmt=""
        call_stack=";
        for (no=1; no<=num;no++) {
                call_stack = call_stack dlmtga [no]
                dlmt = DELIMITER
        }
        printf("%s\n", call_stack);
}
'

find.-name "*.c" | ./call_stack.sh

func()
func(), printf()
func(), func2()
func(), n_sub()
func(), n_sub(), func3()
func(), n_sub(), printf()
func(), func()*
func2()
func2(), printf()
func2(), n_sub()
func2(), n_sub(), func3()
func2(), n_sub(), printf()
func2(), func()
func3()
func3(), printf()
func3(), func2()
func3(), n_sub()
func3(), n_sub(), printf()
main()
main(), printf()
main(), n_sub()
main(), n_sub(), printf()
main(), func()
main(), func2()

for file in *.c; docflow${file}; done

 func()<int func() at func.c:7>(R):
    printf()
    func2()
    n_sub()<int n_sub() at func.c:14>:
        func3()
        printf()
    func()<int func() at func.c:7>(recursive:see1)
func2()<int func2(void) at func2.c:7>:
    printf()
    n_sub()<int n_sub() at func2.c:13>:
        func3()
        printf()
    func()
func3()<int func3() at func3.c:5>:
    printf()
    func2()
    n_sub()<int n_sub() at func3.c:11>:
        printf()
main()<int main(intargc, char*argv[]) at main.c:6>:
    printf()
    n_sub()<int n_sub() at main.c:13>:
        printf()
    func()
    func2()