Serious Memory Clash: Variables clashing in C - c

struct Message
{
char type;
double idNum;
char *Time;
char *asset;
bool BS;
float price1;
int shares1;
float price2;
int shares2;
};
typedef struct Message Message;
struct Asset
{
oBook *OrderBook;
Trade *TradeBook; //will point to the latest trade
int QtyTraded;
float ValueTraded;
char* Time;
};
typedef struct Asset Asset;
int main(int argc, char*argv[])
{
Message* newMessage;
Asset* Check;
//manipulation and initialization of Check, so that it holds proper values.
newMessage = parser("N,2376,01/02/2011 09:15:01.342,JPASSOCIAT FUTSTK 24FEB2011,B,84.05,2000,0,0",newMessage);
// MessageProcess(newMessage,AssetMap);
printf("LAST TRADE ADDRESS %p LAST TRADE TIME %s\n",Check->TradeBook,Check->Time);
}
Message* parser(char *message,Message* new_Message)
{
char a[9][256];
char* tmp =message;
bool inQuote=0;
int counter=0;
int counter2=0;
new_Message = (Message*)malloc(sizeof(Message));
while(*tmp!='\0')
{
switch(*tmp)
{
case ',': if(!inQuote)
{
a[counter][counter2]='\0';
counter++;
counter2=0;
}
break;
case '"':
inQuote=!inQuote;
break;
default:
a[counter][counter2]=*tmp;
counter2++;
break;
}
tmp++;
}
a[counter][counter2]='\0';
new_Message->type = *a[0];
new_Message->Time = &a[2][11];
new_Message->asset = a[3];
if(*a[4]=='S')
new_Message->BS = 0;
else
new_Message->BS = 1;
new_Message->price1=atof(a[5]);
new_Message->shares1=atol(a[6]);
new_Message->price2=atof(a[7]);
new_Message->shares2=atol(a[8]);
new_Message->idNum = atoi(a[1]);
return(new_Message);
}
Here there is a serious memory clash, in two variables of different scope. I have investigated using gdb and it seems the address of new_Message->Time is equalling to the address of Check->Time.
They both are structures of different types I am trying to resolve this issue, because, when parser changes the value of new_Message->Time it manipulates the contents of Check->Time
Please do suggest how to solve this problem. I have lost(spent) around 10 hours and counting to resolve this issue, and tons of hair.
Soham
EDIT STRUCTURE DEF ADDED

You're using an address of the stack allocated object to initialize new_Message->Time = &a[2][11];

Although you don't show us how you initialize Check which limits the amount of help we can give, there is an unnecessary parameter to parse() which you can remove.
int main(int argc, char **argv)
{
Message *newMessage;
Asset *Check;
[...]
newMessage = parser("N,2376...,0,0", newMessage);
[...]
}
Message *parser(char *message, Message *new_Message)
{
[...]
new_Message = (Message *)malloc(sizeof(Message));
[...]
return(new_Message);
}
When you look at that skeleton, it may be easier to see that:
a. The value in main() passed to parser() as newMessage is undefined because the local variable has not been initialized, but
b. It doesn't matter much because the first thing that happens in parser() is that a value is allocated and assigned to the function's copy of the uninitialized value (new_Message), thus initializing the value used in parser().
So, the code is 'safe', but could be written as:
int main(int argc, char **argv)
{
Message *newMessage;
Asset *Check;
[...]
newMessage = parser("N,2376...,0,0");
[...]
}
Message *parser(char *message)
{
[...]
Message *new_Message = (Message *)malloc(sizeof(Message));
[...]
return(new_Message);
}
It is best not to pass values to functions that are not used.
Also, most people either use underscores to separate words in names or use camelCase names, but not usually camel_Case which combines both.

Related

C mutating struct properties by reference

I'm learning pointers in C and i came across a confusion between pointers X struts X functions
The goal: creating two structs and mutate properties inside them.
The path I'm going: I am creating these two structs and then passing its memory addresses to the mutate function, the function then prints and mutates some properties of these structs.
Result I get:
1: The name of the struct created is nod being entirely printed and its of the wrong struct passed, and the life property is not properly changed and printed to the screen.
2: On the terminal I get "Segmentation Fault", not sure why but I'm pretty sure its something wrong I did.
Here's my code:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
typedef struct {
int power;
int life;
char name[];
} Hero;
void attackHero(Hero *hero, int *power) {
(*hero).life = (*hero).life - *power;
printf("Damage: %d\n", *power);
printf("Attacked hero: %s\n", (*hero).name);
printf("Hero's remaining life: %d\n", (*hero).life);
};
int main () {
Hero flash;
flash.power = 250;
flash.life = 500;
strcpy(flash.name, "The Flash");
Hero batman;
batman.power = 380;
batman.life = 700;
strcpy(batman.name, "Batman arkham knight");
attackHero(&flash, &batman.power);
return 0;
}
Result printed to the terminal (Vscode + gcc):
Here is the warning that I get when I compile your original code:
1.c:25:2: warning: ‘__builtin_memcpy’ writing 10 bytes into a region of size 0 overflows the destination [-Wstringop-overflow=]
25 | strcpy(flash.name, "The Flash");
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1.c:30:2: warning: ‘__builtin_memcpy’ writing 21 bytes into a region of size 0 overflows the destination [-Wstringop-overflow=]
30 | strcpy(batman.name, "Batman arkham knight");
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
If you want to use the flexible array then you have to allocate space for it like this:
int main () {
Hero *flash = malloc(sizeof(*flash) + sizeof("The Flash"));
flash->power = 250;
flash->life = 500;
strcpy(flash->name, "The Flash");
Hero *batman = malloc(sizeof(*flash) + sizeof("Batman arkham knight"));
batman->power = 380;
batman->life = 700;
strcpy(batman->name, "Batman arkham knight");
attackHero(flash, &batman->power);
free(flash);
free(batman);
}
Here there the resulting code refactored a bit, and I added a error check for malloc:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
typedef struct {
int power;
int life;
char name[];
} Hero;
Hero *createHero(int power, int life, const char *name) {
Hero *h = malloc(sizeof(*h) + strlen(name) + 1);
if(!h) {
printf("malloc failed\n");
exit(1);
}
h->power = power;
h->life = life;
strcpy(h->name, name);
return h;
}
void attackHero(Hero *hero, int power) {
hero->life -= power;
printf(
"Damage: %d\n"
"Attacked hero: %s\n"
"Hero's remaining life: %d\n",
power,
hero->name,
hero->life
);
};
int main(void) {
Hero *flash = createHero(250, 500, "The Flash");
Hero *batman = createHero(380, 700, "Batman arkham knight");
attackHero(flash, batman->power);
free(flash);
free(batman);
}
Alternatively use a fixed array (char [64] as suggested by #Diego) or a char * and allocate space to it. The former only needs 2 lines of code change from the original:
// largest name in use
#define NAME_LEN sizeof("Batman arkham knight")
typedef struct {
int power;
int life;
char name[NAME_LEN];
} Hero;
Whole lotta malloc() going on. Since the hero’s names are string literals (and assuming they don’t change), just change name[]; to const char *name in the structure and initialize via simple assignment:
flash.name = "The Flash";
batman.name = "Batman arkham knight";
No worries about malloc() failures, name sizes or free() requirements.

How do I use the value of a variable in a function else where?

I have a certain program that lets you register members and save their name and birthdate into arrays. The particular function that does this registration uses the following code;
char regmember (struct member a[])
{
int i = 0;
char wow;
do
{
//registration
printf("\n Do you want to add someone else (y/n):");
scanf(" %c",&wow);
i++
}while(wow != 'n');
int nrofmembers = i;
return nrofmembers;
}
-> I save the user input by using
scanf("%s",a[i].name) and scanf("%d",&a[i].ID);
which is why I am using i++. As you realize, the int variable i, will hold the number of members who have been registered. I want to utilize this info in order to use it in loops in other functions, so I went on to save the value of i in another int variable...
int nrofmembers = i;
My problem is, I can't use that variable (nrofmembers) else where, even though I tried returning it, any advice?
you need both to get i in parameter and to return the new value, you can do
int regmember (struct member a[], int i)
{
... use and modify i
return i;
}
or using it as an input-output variable
void regmember (struct member a[], int * i)
{
... use and modify *i
}
In the first case the caller do for instance :
int i = 0;
for (...) {
...
i = regmember(..., i);
...
}
and in the second case :
int i = 0;
for (...) {
...
regmember(..., &i);
...
}
Suppose you keep the members in a global array, then you can manage how many members are in your array also as a global variable, for example
struct member gMembers[MAX_MEMBERS];
int gnMembers;
Your function can now operate on this array directly:
int regmember (void)
{
if (gnMembers < MAX_MEMBERS)
{
// add member
if (scanf("%s",gMembers[gnMembers].name)==1
&& scanf("%d",&gMembers[gnMembers].ID)==1) {
gnMembers++;
return 1; // success
}
}
return 0; // array full or scanf error
}

Array of jump tables in C

I'm trying to optimize access to some jump tables I have made, they are as follows:
int (*const usart_ctrl_table[USART_READ_WRITE_CLEAR])() =
{zg_usartCtrlRead, zg_usartCtrlWrite, zg_usartCtrlClr};
int (*const usart_frame_table[USART_READ_WRITE_CLEAR])() =
{zg_usartFrameRead, zg_usartFrameWrite, zg_usartFrameClr};
int (*const usart_trig_ctrl_table[USART_READ_WRITE_CLEAR])() =
{zg_usartTrigctrlRead, zg_usartTrigctrlWrite, zg_usartTrigctrlClr};
As you can see, the functions are for accessing a usart peripheral on a hardware level and are arranged in the table in the order of read/write/clear.
What I am attempting to do is have another jump table of jump tables, this way I can either run through initializing all the usart's registers in startup or simply change a single register later if desired.
i.e.
<datatype> (*usart_peripheral_table[<number of jump tables>])() =
{usart_ctrl_table, usart_frame_table, usart_trig_ctrl_table};
This way I can expose that table to my middleware layer, which will help maintain a standard across changing HALs, and also I can use a define to index this table i.e.
fn_ptr = usart_peripheral_table[CTRL_TABLE]
fn_ptr[WRITE](bitmask);
fn_ptr[READ](buffer);
As you may have already guessed, I am struggling to figure out how to construct this table. I figured it is one of two things:
Another simple array of pointers, as even a jump table itself is just an array of pointers. Hence my initialization would be:
const int* (*usart_peripheral_table[<number of jump tables])() =
{usart_ctrl_table, usart_frame_table, usart_trig_ctrl_table};
However this doesn't seem to be working. Then I thought:
An array of pointers to pointers. So I tried all kinds of combos:
const int**(*usart_perip...
const int**(usart_perip...
const int** (*usart_peripheral_table[<number of jump tables])() =
{&usart_ctrl_table, &usart_frame_table[0], usart_trig_ctrl_table};
Nothing seems to work. Do I need to store the address of the lower jump tables in yet another pointer before assigning that variable to a pointer-to-pointer array? i.e.
int* fn_ptr = usart_ctrl_table;
<dataytype>(*const usart_periph[<number>])() = {fn_ptr};
Thanks in advance, any help would be greatly appreciated.
MM25
EDIT:
const int** (*const peripheral_table[1])() =
{&usart_ctrl_table[0]};
const int** (*const peripheral_table[1])() =
{usart_ctrl_table};
The above both give the error "initialization from incomaptible pointer type", as do all other combinations I have tried
You might find that defining a typedef for your function pointers makes your code easier to read and maintain (although I’ve seen people recommend against it too):
#include <stdio.h>
#include <stdlib.h>
#define UART_RWC 3U
typedef int (*uart_ctl_func)(void);
int uart_read(void)
{
printf("Read.\n");
fflush(stdout);
return 0;
}
int uart_write(void)
{
printf("Write.\n");
fflush(stdout);
return(0);
}
int uart_clear(void)
{
printf("Clear.\n");
fflush(stdout);
return 0;
}
uart_ctl_func uart_ctl_jump_table[][UART_RWC] = {
{ uart_read, uart_write, uart_clear },
{ uart_read, uart_write, uart_clear }
};
int main(void)
{
uart_ctl_jump_table[0][1](); // Write.
uart_ctl_jump_table[1][0](); // Read.
uart_ctl_jump_table[1][2](); // Clear.
return EXIT_SUCCESS;
}
The next step might be to make the jump table a struct so you end up writing Uart_ctl_table.frame.read(), or to at least define an enum for the constants.
#include <stdio.h>
#include <stdlib.h>
#define UART_RWC 3U
typedef int (*uart_ctl_func)(void);
int uart_read(void)
{
printf("Read.\n");
fflush(stdout);
return 0;
}
int uart_write(void)
{
printf("Write.\n");
fflush(stdout);
return(0);
}
int uart_clear(void)
{
printf("Clear.\n");
fflush(stdout);
return 0;
}
typedef struct {
uart_ctl_func read;
uart_ctl_func write;
uart_ctl_func clear;
} uart_ctl_set_t;
typedef struct {
uart_ctl_set_t ctrl;
uart_ctl_set_t frame;
uart_ctl_set_t trig;
} uart_ctl_table_t;
const uart_ctl_table_t uart_ctl_table = {
.ctrl = { uart_read, uart_write, uart_clear },
.frame = { uart_read, uart_write, uart_clear },
.trig = { uart_read, uart_write, uart_clear }
};
int main(void)
{
uart_ctl_table.ctrl.write(); // Write.
uart_ctl_table.frame.read(); // Read.
uart_ctl_table.trig.clear(); // Clear.
return EXIT_SUCCESS;
}
Just add a * like you added [] when defining an array.
int zg_usartCtrlRead();
int zg_usartCtrlWrite();
int zg_usartCtrlClr();
int zg_usartFrameRead();
int zg_usartFrameWrite();
int zg_usartFrameClr();
int zg_usartTrigctrlRead();
int zg_usartTrigctrlWrite();
int zg_usartTrigctrlClr();
int (*const usart_ctrl_table[])() =
{zg_usartCtrlRead, zg_usartCtrlWrite, zg_usartCtrlClr};
int (*const usart_frame_table[])() =
{zg_usartFrameRead, zg_usartFrameWrite, zg_usartFrameClr};
int (*const usart_trig_ctrl_table[])() =
{zg_usartTrigctrlRead, zg_usartTrigctrlWrite, zg_usartTrigctrlClr};
int (* const * const usart_peripheral_table[])() =
{usart_ctrl_table, usart_frame_table, usart_trig_ctrl_table};
Usage:
usart_peripheral_table[1][2](5, 1, 3, 5, 6);
Btw, an empty parameter list on function declaration () means unspecified number and type of arguments. Do (void) if you want no arguments passed to your function.
This:
const int* (*usart_peripheral_table[<number of jump tables])();
Is an array of functions pointers that take unspecified number of arguments and return a pointer to constant integer.
This:
const int** (*usart_peripheral_table[<number of jump tables])()
Is an array of function pointers that take unspecified number of arguments and return a pointer to a pointer to a constant integer.
You can also go with a 2D array:
int (* const usart_peripheral_table_2d[][3])() = {
{
zg_usartCtrlRead, zg_usartCtrlWrite, zg_usartCtrlClr,
}, {
zg_usartFrameRead, zg_usartFrameWrite, zg_usartFrameClr,
}, {
zg_usartTrigctrlRead, zg_usartTrigctrlWrite, zg_usartTrigctrlClr,
},
};
But maybe you want to write accessor functions that will return a pointer to an array of functions. Nothing simpler!
#include <stddef.h>
int (*usart_ctrl_table_get(size_t idx))() {
return usart_ctrl_table[idx];
}
int (*usart_frame_table_get(size_t idx))() {
return usart_frame_table[idx];
}
int (*usart_trig_ctrl_table_get(size_t idx))() {
return usart_trig_ctrl_table[idx];
}
int (* const (* const usart_peripheral_table_indirect[])(size_t))() = {
usart_ctrl_table_get,
usart_frame_table_get,
usart_trig_ctrl_table_get,
};
Usage sample:
int main() {
usart_peripheral_table_indirect[2](1)();
}

Freeing memory gives segmentation fault [closed]

Closed. This question needs debugging details. It is not currently accepting answers.
Edit the question to include desired behavior, a specific problem or error, and the shortest code necessary to reproduce the problem. This will help others answer the question.
Closed 4 years ago.
Improve this question
I've been trying to work with structures, pointers and memory in C.
I have created this structure
typedef struct {
int id;
char *name;
} Object;
here is constructor
void object_ctor(Object *o, int id, char *name)
{
o->id = id;
o->name = malloc(sizeof(name));
if(sizeof(o->name)!=sizeof(name))
{
o->name=NULL;
}
else
{
strcpy(o->name, name);
}
}
here is decleration of o1
char tmp_name[] = "Hello 1";
Object o1;
object_ctor(&o1, 1, tmp_name);
here is destructor
void object_dtor(Object *o)
{
if(o->name != NULL)
{
free(o->name);
o->name = NULL;
}
}
printing object
void print_object(Object *o)
{
printf("ID: %d, NAME: %s\n", o->id, o->name);
}
calling copy
Object copy;
print_object(object_cpy(&copy, &o1));
and I´m trying create a copy of one structure to another (I have already constructed them).
Object *object_cpy(Object *dst, Object *src)
{
if(src!=NULL)
{
const size_t len_str=strlen(src->name)+1;
dst->name = malloc(10000000);
dst->id = src->id;
strncpy (dst->name, src->name,len_str);
}
if (strcmp(dst->name,src->name)!=0)
{
dst->name = NULL;
}
return dst;
}
But then when I'm trying to free both copy and original src I get a segmentation fault. I've been trying to run it through gdb and it said that I'm freeing same memory twice so I assume that the code for copying is wrong, but I don't know where.
And here is code that gives me segmentation fault
printf("\nCOPY EMPTY\n");
object_dtor(&copy);
o1.id = -1;
free(o1.name);
o1.name = NULL;
object_cpy(&copy, &o1);
print_object(&copy);
print_object(&o1);
I´m including these libraries
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
I'm using the std=c99 flag for to compile.
There is at least a problem here:
void object_ctor(Object *o, int id, char *name)
{
o->id = id;
o->name = malloc(sizeof(name));
if (sizeof(o->name) != sizeof(name))
{
o->name = NULL;
}
else
{
strcpy(o->name, name);
}
}
sizeof(name) is not the length of the string pointed by name. You need strlen(name) + 1 (+1 for the NUL terminator).
And your test if (sizeof(o->name) != sizeof(name)) is pointless, and I'm not sure what you're trying to achieve here.
You probably want this:
void object_ctor(Object *o, int id, char *name)
{
o->id = id;
o->name = malloc(strlen(name) + 1);
if (o->name != NULL)
strcpy(o->name, name);
}
There are similar problems in object_cpy:
pointless use of strncpy
pointless allocation of a 10Mb buffer
pointless test strcmp(dst->name, src->name)
You probably want this:
Object *object_cpy(Object *dst, Object *src)
{
if (src != NULL)
{
const size_t len_str = strlen(src->name) + 1;
dst->name = malloc(len_str);
if (dst->name != NULL)
{
dst->id = src->id;
strcpy(dst->name, src->name);
}
}
return dst;
}
With these corrections following code works fine:
int main()
{
char tmp_name[] = "Hello 1";
Object o1, copy;
object_ctor(&o1, 1, tmp_name);
object_cpy(&copy, &o1);
print_object(&copy);
print_object(&o1);
object_dtor(&o1);
object_dtor(&copy);
}
Event if this is not directly an answer to your problem, I'll give you how I organize my code in order to avoid memory problem like yours.
First, it all resolve around a structure.
To each structure, if needed, I do a "Constructor" and a "Destructor".
The purpose of the constructor is simply to set the structure in a coherent state. It can't never fail (implying that any code that could fail, like malloc, should not be in the constructor).
The purpose of the destructor is to clean the structure.
One little trick that I like to use is to put the constructor in a macro, allowing me to do something like 'Object var = OBJET_CONSTRUCTOR'.
Of course, it's not alway possible, it's up to you to be carreful.
For your code, it could be :
typedef struct {
int id;
char *name;
} Object;
#define OBJECT_CONSTRUCTOR {.id = -1,\ \\ Assuming -1 is relevant in your case, like an error code or a bad id value. Otherwise, it's useless.
.name = NULL}
void Object_Constructor(Object *self)
{
Object clean = OBJECT_CONSTRUCTOR;
*self = clean;
}
void Object_Destructor(Object *self)
{
free(self->name);
}
Here we go.
How to use it is simple : You always begin by the constructor, and you alway end by the destructor. That's why it's useless to set the char pointer "name" to NULL in the destructor, because it should not be used after by any other function that the constructor.
Now, you can have "initialisation" function. You can do a plain initialisation (it is your constructor function), or a copy initialisation, etc etc
Just keep in mind that the structure have been called into the constructor. If not, it's the developer fault and you do not have to take that in count.
A behavior that can be nice is, in case of error, to not modify the structure.
Either the structure is entierly modified in succes, or not at all.
For complex structure that can fail at many point, you can do that by "swapping" the result at the end.
void Object_Swap(Object *first, Object *second)
{
Object tmp = OBJECT_CONSTRUCTOR;
tmp = *fisrt;
*first = *second;
*second = tmp;
}
bool Object_InitByPlainList(Object *self, int id, consr char *name)
{
Object newly = OBJECT_CONSTRUCTOR;
bool returnFunction = false;
newly.id = id;
if (!(newly.name = strdup(name))) {
printf("error : %s : strdup(name) : name='%s', errno='%s'.\n", __func__, name, strerror(errno));
goto END_FUNCTION;
}
// Success !
Object_Swap(self, &newly);
returnFunction = true;
/* GOTO */END_FUNCTION:
Object_Destructor(&newly);
return (returnFunction);
}
It may be seem overcomplicated at the first glance, but that organization allow you to add more futur step "that can fail" cleanly.
Now, you can even do something this simply :
bool Object_InitByCopy(Object *dst, Object *src)
{
return (Object_InitByPlainList(dst, src->id, src->name));
}
All you have to do is to say in the documentation :
The first function to be called have to be "Object_Constructor"
After the "Object_Constructor", only the "Object_Init*" function can be called.
The last function to be call have to be "Object_Destructor"
That's all. You can add any "Object_*" function that you whant, like :
void Object_Print(const Object *self)
{
printf("ID: %d, NAME: %s\n", self->id, self->name);
}
Hope this organization will solve your memory problem.
An example :
int main(void)
{
Object test = OBJECT_CONSTRUCTOR;
Object copy = OBJECT_CONSTRUCTOR;
if (!Object_InitByPlainList(&test, 1, "Hello World !")) {
// The function itself has logged why it has fail, so no need to add error printf here
return (1);
}
Object_Print(&test);
if (!Object_Copy(&copy, &test)) {
return (1);
}
Object_Destructor(&test);
Object_Destructor(&copy);
return (0);
}

User entered string run a particular function in c

Guys so I'm working on the web service assignment and I have the server dishing out random stuff and reading the uri but now i want to have the server run a different function depending on what it reads in the uri. I understand that we can do this with function pointers but i'm not exactly sure how to read char* and assign it to a function pointer and have it invoke that function.
Example of what I'm trying to do: http://pastebin.com/FadCVH0h
I could use a switch statement i believe but wondering if there's a better way.
For such a thing, you will need a table that maps char * strings to function pointers. The program segfaults when you assign a function pointer to string because technically, a function pointer is not a string.
Note: the following program is for demonstration purpose only. No bounds checking is involved, and it contains hard-coded values and magic numbers
Now:
void print1()
{
printf("here");
}
void print2()
{
printf("Hello world");
}
struct Table {
char ptr[100];
void (*funcptr)(void)
}table[100] = {
{"here", print1},
{"hw", helloWorld}
};
int main(int argc, char *argv[])
{
int i = 0;
for(i = 0; i < 2; i++){
if(!strcmp(argv[1],table[i].ptr) { table[i].funcptr(); return 0;}
}
return 0;
}
I'm gonna give you a quite simple example, that I think, is useful to understand how good can be functions pointers in C. (If for example you would like to make a shell)
For example if you had a struct like this:
typedef struct s_function_pointer
{
char* cmp_string;
int (*function)(char* line);
} t_function_pointer;
Then, you could set up a t_function_pointer array which you'll browse:
int ls_function(char* line)
{
// do whatever you want with your ls function to parse line
return 0;
}
int echo_function(char* line)
{
// do whatever you want with your echo function to parse line
return 0;
}
void treat_input(t_function_pointer* functions, char* line)
{
int counter;
int builtin_size;
builtin_size = 0;
counter = 0;
while (functions[counter].cmp_string != NULL)
{
builtin_size = strlen(functions[counter].cmp_string);
if (strncmp(functions[counter].cmp_string, line, builtin_size) == 0)
{
if (functions[counter].function(line + builtin_size) < 0)
printf("An error has occured\n");
}
counter = counter + 1;
}
}
int main(void)
{
t_function_pointer functions[] = {{"ls", &ls_function},
{"echo", &echo_function},
{NULL, NULL}};
// Of course i'm not gonna do the input treatment part, but just guess it was here, and you'd call treat_input with each line you receive.
treat_input(functions, "ls -laR");
treat_input(functions, "echo helloworld");
return 0;
}
Hope this helps !

Resources