Решил модифицировать код

//---------------------------------------------------------------------------
 
#include <vcl.h>
#include <stdio.h>
#pragma hdrstop
#include "av.h"
 
#include "Unit2.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm2 *Form2;
//---------------------------------------------------------------------------
__fastcall TForm2::TForm2(TComponent* Owner)
        : TForm(Owner)
{
}
//---------------------------------------------------------------------------
 
 
void __fastcall TForm2::Button1Click(TObject *Sender)
{
int i;
int y;
if (CheckBox1->Checked == true)
{
  char str_file[100];
FILE* fp = fopen("processinfo.db","r");
if(fp != NULL)
{
 
char ch;
while((ch = getc(fp)) != EOF)
str_file[i++]=ch;
str_file[i] = '\0';
printf(str_file);
}
else Memo1->Lines->Add("Невозможно открыть базу данных");
fclose(fp);
 
 
 
while (y==i)
{
 StopAV(str_file[y]);
}
 
fclose(fp);
}
}
}
 
//---------------------------------------------------------------------------

[C++ Warning] av.h(29): W8004 'term' is assigned a value that is never used
[C++ Error] Unit2.cpp(45): E2034 Cannot convert 'int' to 'char *'
[C++ Error] Unit2.cpp(45): E2342 Type mismatch in parameter 'antivirus' (wanted 'char *', got 'char')

int i=0,y=0;

char str_file[100];

str_file[i++]=ch;
str_file[i] = '\0';
StopAV(str_file[i]);

StopAV(str_file); // char* antivirus = str_file

void __fastcall TForm2::Button1Click(TObject *Sender)
{
int i;
char* Pfile;
 
if (CheckBox1->Checked == true)
{
  char str_file[100];
FILE* fp = fopen("processinfo.db","r");
if(fp != NULL)
{
 
char ch;
while((ch = getc(fp)) != EOF)
str_file[i++]=ch;
str_file[i] = '\0';
Pfile = str_file[i];
StopAV(file);
Memo1->Lines->Add(str_file);
}

[C++ Error] Unit2.cpp(37): E2034 Cannot convert 'char' to 'char *'
[C++ Error] Unit2.cpp(38): E2108 Improper use of typedef 'file'
[C++ Warning] Unit2.cpp(51): W8004 'Pfile' is assigned a value that is never used

Pfile = str_file[i];

#include <string>
#include <fstream>
 
//............
 
std::ifstream inFile("processinfo.db");
std::string procName;
 
while( std::getline(inFile, procName) )
    StopAV( procName.c_str() ); // !!!
 
inFile.close();

#include <string>
#include <fstream>
#include <list>
#include <iterator>
 
typedef std::list<std::string> ProcList;
 
//...
 
std::ifstream inFile("processinfo.db");
ProcList procList( (std::istream_iterator<std::string>(inFile)),
                    std::istream_iterator<std::string>() );
inFile.close()
 
for(ProcList::iterator item = procList.begin(); item != procList.end(); ++item)
    StopAV( item->c_str() ); // !!!

cannot to convert const char to char*