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Date: Tue, 21 Dec 1993 09:55:03 CDT
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Subject: OCTOBER93.CBUGS
To: EVERHART@arisia.gce.com


       int     *x = new int [20];     // Set up an array of 20 ints
       ...                            // Do useful stuff with the array              
       delete [] x;                   // Return the memory to the free 
                                      // store. 
==

        void    set_new_handler( void (*)(void)) 

==

        char    string[80]; 
        ...
        scanf("%s",string);

==

        char    string[80];
        ... 
        cin >> string; 


==

        istream &get(char *ptr, int len, char delim) 
        istream &getline(char *ptr, int len, char delim)


==

$
$ type new_handler.cxx 
// Program illustrating the establishment of a "new" 
// handler 
#include <stdio.h> 
#include <stdlib.h> 
#include <new.hxx> 


void   mem_problem(void); 
in    main(void) 
{    int   i;
     int   *x;

// Establish a handler function for problems with new 
// i.e. returns a NULL value
    set_new_handler(mem_problem); 
// Ask for memory which is too big
    i=2000000000;
    x = new int [i]; 
// Should not get here
    printf("last element = %d\n",x[i-1]); 
    return(EXIT_SUCCESS); 
} 
// Generate system dependent message 
#ifdef __VMS 
const  char  *local_msg = "See the system manager and ask "
                          "her/him to increase\n"
"The sysgen parameter VIRTUALPAGECNT.\n;
#else 
const  char  *local_msg = "Locate the UNIX Guru and pray!\n"; 
#endif 
void  mem_problem(void) 
{                                                                     
    perror("Memory allocation failure detected, aborting!\n");        
    fprintf(stderr,local_msg); 
// Lunch the program 
    exit(EXIT_FAILURE); 
}                                                                     
$ 
$ 
$ cxx new_handler 
$ link new_handler 
$ run new_handler 
Memory allocation failure detected, aborting! 
: not enough core 
See the system manager and ask her/him to increase 
The sysgen parameter VIRTUALPAGECNT. 
$ 
$ 
 
==

$ 
$ type new_prob.cxx 
// Program illustrating the establishment of a "new" 
// handler 
#include <stdio.h> 


#include <stdlib.h> 
#include <new.hxx> 
void  mem_problem(void); 
int   main(void) 
{ 
    int   i;
    int   *x;

// Establish a handler function for problems with new 
// i.e. returns a NULL value 
    set_new_handler(mem_problem); 
// Keep asking for memory until too much
    i=20000; 
    for(int j=0;j<10000;j++) 
        x = new int [i]; 
// Should not get here 
    printf("last element = %d\n",x[i-1]); 
    return(EXIT_SUCCESS); 
} 
// Generate system dependent message 
#ifdef __VMS 
const  char  *local_msg = "See the system manager and ask " 
                  "her/him to increase\n"
                  "The sysgen parameter VIRTUALPAGECNT.\n"; 
#else 
const  char  *local_msg = "Locate the UNIX Guru and pray!\n"; 
#endif 
void  mem_problem(void) 
{ 
    perror("Memory allocation failure detected, aborting!\n");        
    fprintf(stderr,local_msg); 
// Lunch the program 
    exit(EXIT_FAILURE); 
}                                                                     
$ $ !Note: The bogus error message 
$ cxx new_prob 
$ link new_prob 
$ run new_prob 
%SYSTEM-F-ACCVIO, access violation, reason mask=05, virtual
address=7FF248BC, PC=0007EC16, PSL=0BC00009 

 Improperly handled condition, image exit forced. 
    Signal arguments        Stack contents 
%SYSTEM-F-ROPRAND, reserved operand fault at PC=80000010, PSL=03C00004 
 Improperly handled condition, image exit forced. 
    Signal argument        Stack contents 
    Number = 0000000         80223840                                 
    Name  = 00000454         00000002
            80000010         7FF273F0
            03C00004         7FF273D8                                 
                             00000004 


                             7FF270FC 
                             00000007
                             00000000 
                             80223C00
                             
    Register dump 
    
    R0 = 03C00000 R1 = 00040000 R2 = 000000FC R3 = 7FF274EC           
    R4 = 00000000 R5 = 00000004 R6 = 7FF275EC R7 = 7FF2746D           
    R8 = 7FF27600 R9 = 7FF27454 R10= 7FF274EC R11= 7FF274A8           
    AP = 7FF27394 FP = 7FF27354 SP = 7FF273C8 PC = 80000010           
    PSL= 03C00004 

$ 
$ 
 
==

$ type new_kluge.cxx 
// Program illustrating the establishment of a "new" 
// handler 
#include <stdio.h> 
#include <stdlib.h>
#include <errno.h> 
#include <new.hxx> 
void  mem_problem(void); 
int   main(void) 
{
    int   i; 
    int   *x; 

// Establish a handler function for problems with new 
// i.e. returns a NULL value                                          
    set_new_handler(mem_problem); 
//******* Kluge fix 
// Send a warning, to activate perror and prevent later problems      
    errno = EINPROGRESS; 
    perror("Setting up arrays"); 
//******* 

// Keep asking for memory until too much 
    i=20000; 
    for(int j=0;j<10000;j++) 
        x = new int [i]; 
// Should not get here
    printf("last element = %d\n",x[i-1]);                             
    return(EXIT_SUCCESS); 
} 
// Generate system dependent message 


#ifdef __VMS 
const  char  *local_msg = "See the system manager and ask " 
                  "her/him to increase\n"                             
                  "The sysgen parameter VIRTUALPAGECNT.\n"; 
#else 
const  char  *local_msg = "Locate the UNIX Guru and pray!\n"; 
#endif 
void   mem_problem(void) 
{ 
     perror("Memory allocation failure detected, aborting!\n");       
     fprintf(stderr,local_msg); 
// Lunch the program 
    exit(EXIT_FAILURE); 
}                                                                     
$ cxx new_kluge 
$ link new_kluge 
$ r new_kluge 
Setting up arrays: operation in progress 
Memory allocation failure detected, aborting! 
: not enough core 
See the system manager and ask her/him to increase 
The sysgen parameter VIRTUALPAGECNT. 
$ 
 
==

[Figure 4]

$ type read_bad.cxx 
#include <stdlib.h> 
#include <iostream.h> 

const static  int  max_lines = 5; 
const static  int  in_bufsize = 30; 
int   main(void) 
{
    char  strings[max_lines][in_bufsize]; 
    char  last_char; 
// Prompt user                                                        
    cout << "Enter up to "<<max_lines <<" lines. (or eof to end)\n"; 
// read up to 5 lines or until EOF 
    for(int i=0;i<max_lines;i++)                                      
    { 
// Read up to, but NOT including, newline or up to bufsize characters 
        cin.get(strings[i],in_bufsize,'\n'); 

// If at end-of-file terminate loop
        if((last_char = cin.get())==EOF ) 
        { 
            break; 
        } 


// If not newline the input is too large
        else if(last_char!='\n') 
        { 
// Skip the overflow 
             cin.ignore(BUFSIZ,'\n'); 
// Notify user of truncation 
            cerr<<"Buffer overflow\n"; 
            cerr<<"Line truncated\n"; 
        } 
     } 
// Print them back
    cout << "Here's your lines:\n";
    for(int j=0;j<i;j++)
    {
        cout<<strings[j]<<'\n';; 
    }                                                                 
    return(EXIT_SUCCESS); 
} 
$ 
$ cxx read_bad 
$ link read_bad 
$ $ !Sample run 1 
$ run read_bad 
Enter up to 5 lines. (or eof to end) 
line 1 
line 2 
line 3 
^Z 
Here's your lines: 
line 1 
line 2 
line 3 
$ 
$ !Sample run 2 
$ run read_bad 
Enter up to 5 lines. (or eof to end) 
line 1 
lllllllllllllllloooooonngg line aaaaaaaaaaaaaaaaaa 
short line 
Buffer overflow 
Line truncated 
line 4 
^Z 
Here's your lines: 
line 1 
lllllllllllllllloooooonngg linshort line 
short line 
line 4 
$ !Sample run 3 
$ run read_bad 
Enter up to 5 lines. (or eof to end) 


123456789012345678901234567890Characters after 30 
another line 
Buffer overflow 
Line truncated 
^Z 
Here's your lines: 
123456789012345678901234567890another line 
another line 
$ 
 
==

$ type read_lines.cxx 
// Corrected version of program 
#include <stdlib.h> 
#include <iostream.h> 
const static  int  max_lines = 5; 
const static  int  in_bufsize = 30; 
int     main(void) 
{ 
//************** 
// Compensate for cin.get 
//**************
    char  strings[max_lines][in_bufsize + 1] = {0}; 
    char  last_char;
 
// Prompt user                                                        
    cout << "Enter up to "<<max_lines <<" lines. (or eof to end)\n"; 

// read up to 5 lines or until EOF 
    for(int i=0;i<max_lines;i++)                                      
    { 
// Read up to, but NOT including, newline or up to bufsize characters 
        cin.get(strings[i],in_bufsize,'\n'); 

// If at end-of-file terminate loop
        if((last_char = cin.get())==EOF ) 
        { 
            break;
        } 
// If not newline the input is too large 
        else if(last_char!='\n')                                      
        { 

//***************** 
// Change the order of the I/Os to allow the cerrs to complete 
// prior to the next read. 
// Notify user of truncation 
            cerr<<"Buffer overflow\n"; 


            cerr<<"Line truncated\n"; 
// Skip the overflow
            cin.ignore(BUFSIZ,'\n'); 
        }
    } 
// Print them back
    cout << "Here's your lines:\n"; 
    for(int j=0;j<i;j++) 
    { 
        cout<<strings[j]<<'\n';;
    }
    return(EXIT_SUCCESS); 
} 
$ cxx read_lines 
$ link read_lines $ 
$ ! Sample run 1 
$ run read_lines 
Enter up to 5 lines. (or eof to end) 
line 1 
line 2 
line 3 
^Z 
Here's your lines: 
line 1 
line 2 
line 3 
$ 
$ !Sample run 2 
$ run read_lines 
Enter up to 5 lines. (or eof to end) 
line 1 
llllllooooooooonnnnnnnnngggggggggggg line aaaaaaaaaa 
Buffer overflow 
Line truncated 
short line 
^Z 
Here's your lines: 
line 1 
llllllooooooooonnnnnnnnngggggg 
short line 
$ 
$ ! Sample run 3 
$ run read_lines 
Enter up to 5 lines. (or eof to end) 
123456789012345678901234567890Characters after 30 
Buffer overflow 
Line truncated 
another line 
^Z 
Here's your lines: 
123456789012345678901234567890 


another line 
$