I'm having trouble with declaration and initialization of a struct in Vectors CANoe CAPL. I already know structs from C/C++ but it seems the declaration is a little different in CAPL.
The Vector help function isn't really revealing.
I have a number of CAN IDs (e.g. 0x61A). Every CAN ID is a different number of Signal IDs (e.g. 0xDDF6) assigned. I want to read out cyclic the Signal ID from the CAN IDs and plan to organize this in a convoluted struct.
I already tried out different types of declaration and initialization but every time I get a parse error.
Can you please give me a helping hand for my problem?
Any other ideas to organize my values unlike a struct?
Thank you and regards!
From the CAPL documentation:
Structured types can be declared in CAPL in a similar way to C...
... they may only be used in CAPL programs with CANoe from version 7.0 Service Pack 3.
Example:
variables
{
/* declarating a struct */
struct MyData {
int i;
float f;
};
}
on start
{
/* defining a struct variable and initiliazing the elements */
struct MyData data = {
i = 42,
f = 1.32
};
/* accessing the struct elements */
write("i=%d, f=%f", data.i, data.f);
}
Output:
i=42, f=1.320000
I had a flaw in struct access. Tried to initialize the struct paramters right in the variable declaration routine, not in the on startroutine.
Working code for my multiple data access is now:
variables
{
struct Veh_Database
{
dword ECU;
dword ParamID[8][2];
};
struct Veh_Database ECU_Info[12];
}
on start
{
ECU_Info[0].ECU = 0x1A;
ECU_Info[0].ParamID[0][0] = 0xDD;
ECU_Info[0].ParamID[0][1] = 0xF6;
/* ... */
ECU_Info[1].ECU = 0x12;
ECU_Info[1].ParamID[0][0] = 0xDE;
ECU_Info[1].ParamID[0][1] = 0x9C;
/* ... */
}
Thanks for your help!
Just for completeness: It is also possible to initialize a struct in the variable declaration:
variables
{
struct myStruct
{
dword val;
dword arr[8];
};
struct myStruct myInstance = {1, {1,2,3,4,5,6,7,8}};
}
(tested on CANoe 10)
CAPL allows initialization of variables structures at declaration also at Onstart procedure but we have to follow correct syntax. here is example code
variables
{
struct mydata
{
int a;
int b;
} ak={5,3};
}
on start
{
write("Initial values are %d, %d",ak.a,ak.b);
ak.a=10;
ak.b=20;
write("values after update are %d, %d", ak.a,ak.b);
}
find more details in following video
https://www.youtube.com/watch?v=hRfSqZBZVHA
Related
Is it possible to EXPORT_SYMBOL() a struct that contains a kmalloc array? If yes, what are the things that I need to keep in mind?
This is a psuedo code of what I want to do.
struct test {
int a;
...
uint64_t* data;
}
struct test foo;
EXPORT_SYMBOL(foo);
...
In module1_kthread1_func() I have:
int module1_kthread1_func(void *foo){
...
foo->data = kmalloc(SIZE, GFP_KERNEL);
...
foo->data[var] = 1243;
var++;
...
}
In module2_kthread2_func() I have:
...
extern struct test foo;
...
int module2_kthread2_func(void* foo){
...
for (i=0; i<SIZE; i++)
printk(KERN_INFO "Variable value of %d is %llu", i, foo->data[var]);
...
}
It's definitely possible, yes.
You need to be careful and make sure that code that uses it knows that some of the fields might not be available before they are allocated. That is, check if they are NULL first instead of directly accessing them.
You might want to declare the structure with an explicit initializer, just so that it is obvious what is going on:
struct test foo = {
.a = 123,
.data = NULL // Initialized by function X when Y
};
EXPORT_SYMBOL(foo);
If such fields are compulsory for the structure to be used, you might want to initialize them early on (see here).
I have the following structs:
typedef struct packed {
logic vld;
logic [`ADDR_RNG] addr;
logic [`CMD_RNG] cmd;
logic [`IDX_RNG] idx;
} pkt1Type_t;
typedef struct packed {
logic vld;
logic [`ADDR2_RNG] addr;
logic [`CMD_RNG] cmd;
logic [`IDX_RNG] idx;
} pkt2Type_t;
typedef struct packed {
logic [???] padding;
pkt1Type_t pkt;
} pkt1TypePadded_t;
typedef struct packed {
logic [???] padding;
pkt2Type_t pkt;
} pkt2TypePadded_t;
typedef union packed {
pkt1TypePadded_t pkt1;
pkt2TypePadded_t pkt2;
} pkt_t;
Where ADDR_RNG and ADDR2_RNG can be different.
As I understand it, SV structs for design (synthesizable) need to be of the same size. Is there a programmatic way to compute the size of pkt1Type_t and pkt2Type_t, find the larger of the 2 and then use it as the range literal in the [???] section above?
Or do I need to compute this manually or through the preprocessor `define?
The dilemma here is only one union member needs to be padded to the size of the other member. But you cannot have a struct member with 0 width. So your packed union has to be at least 1-bit wider than the largest member
parameter MAXSIZE = ($bits(pkt1Type_t) > $bits(pkt2Type_t)) ?
$bits(pkt1Type_t) : $bits(pkt2Type_t);
typedef struct packed {
logic [MAXSIZE-$bits(pkt1Type_t):0] padding;
pkt1Type_t pkt;
} pkt1TypePadded_t;
typedef struct packed {
logic [MAXSIZE-$bits(pkt2Type_t):0] padding;
pkt2Type_t pkt;
} pkt2TypePadded_t;
typedef union packed {
pkt1TypePadded_t pkt1;
pkt2TypePadded_t pkt2;
} pkt_t;
There might be better approaches for what you are trying to do (i.e. tagged unions, let construct, but difficult to say without known more what you need to do with this.
I coded an Arduino project for my son and learned about C in the process. All works fine but after dividing up the code into ten files and grouping the variables into structs in each file I'm not able to solve one wish for clarity. We need to empirically determine the best size of an array for storing and averaging port reads so this is what I want:
struct Alarms {
// Configurable parameters
const unsigned int number_of_reads = 24;
// State variables
int reads[number_of_reads]; // Error: invalid use of non-static data member 'Alarms::num_of_reads'
};
It’s simple but doesn't work. I tried flexible array members until I found that that feature is not supported in C++. Arduino compiles with C++. I tried many examples of the 'struct hack' but they all returned errors like this one:
struct Alarms {
// Configurable parameters
int number_of_reads = 24;
// State variables
int reads[];
} ar;
void setup_alarm() {
ar.reads = malloc(sizeof(int) * ar.number_of_reads); // Error: incompatible types in assignment of 'void*' to 'int [0]'
}
That looked promising but I suspect my ignorance is glowing brightly. Most struct hack examples call for declaring the struct and later initializing the struct variables. I’m hoping to not duplicate the struct.
I considered splitting the struct but that would be error prone and, well, another compile error:
struct Alarms2 {
int reads[ar.num_of_reads]; // Error: array bound is not an integer constant before ']' token
} ar2;
An alternative is to size the array and get the size later but it needs an explanation:
struct Alarms {
// Configurable parameters
int reads[ 24 ]; // Put number of reads to average between brackets
// State variables
int number_of_reads;
};
void setup_alarm() {
ar.number_of_reads = sizeof(ar.reads) / sizeof(ar.reads[0]); // this works
}
Is there a way to work the struct hack or some similar solution in Arduino to like achieve the first example?
The size of the struct must be known at compilation time. Const data types in structs can change per instance of the structure, that is why you are getting the invalid use of non-static data member 'Alarms::num_of_reads' when you try to initialize your array. The best way to solve this is to have an init_alarm and destroy_alarm functions. Like so ...
#include <stdio.h>
#include <stdlib.h>
#define DEFAULT_NUM_OF_READS (24)
struct alarm {
// Configurable parameters
const int number_of_reads;
// State variables
int *reads;
};
void init_alarm(struct alarm *alarm)
{
alarm->reads = (int *) malloc(alarm->number_of_reads * sizeof(int));
}
void destroy_alarm(struct alarm *alarm)
{
free(alarm->reads);
}
int main(int argc, char **argv)
{
// When we create our struct, set number_of_reads to default
struct alarm alarm = {.number_of_reads = DEFAULT_NUM_OF_READS, .reads = NULL};
init_alarm(&alarm);
alarm.reads[0] = 13;
alarm.reads[23] = 100;
printf("alarm.reads[0] = %d, alarm.reads[23] = %d\n", alarm.reads[0], alarm.reads[23]);
destroy_alarm(&alarm);
return 0;
}
Note: Inorder to use the designated initializer to initialize a structure you must compile with ANSI (C99) like so ...
gcc --std=c99 test.c -o test
i am new in this and i am working on App of media player and recording app. in which i have shown song list of device in the listview and recording start / stop / play. Now i want to convert that .mp3 recorded file into .mp4 and one image will show on behalf of a video in that file. Help me to achive this i have no idea and i refer many links and i didnt find anything.
Please check this link for your first question:
Why can't we initialize class members at their declaration?
Usually constructor is use to initialize value to data variables of class.
For 2nd Question:
If data member is not initialize after creation of object, It will contain garbage value. So initialize or assign suitable value to as per your need.
Check below code:
#include<iostream>
using namespace std;
class swap_values
{
int a, b, temp;
public:
swap_values(){
a=0;b=0;temp=0;
}
swap_values(int x, int y){
a = x;
b = y;
temp = 0;
}
void swapped()
{
temp = b;
b=a;
a=temp;
}
void print(){
cout<<"a: "<<a<<" b: "<<b<<endl;
}
};
int main()
{
int x =10; int y = 20;
swap_values obj(x, y);
obj.print();
obj.swapped();
obj.print();
return 0;
}
Everything can be done in better ways but just using your code this will work for you -
#include <iostream>
using namespace std;
class Swap {
private:
int a,b,temp;
public:
Swap()
{
a=10;
b=20;
temp=0;
}
void swapNums()
{
temp=a; a=b; b=temp;
cout<<a<<" " <<b<<endl;
}
};
int main() {
Swap s;
s.swapNums();
return 0;
}
You can avoid using class name as some function name. You can instead use constructor without a return type where you can initialise the member variables. swap method looks fine.
i am not able to initialize my variable in class.
class swap
{
int a=10; \\cannot declare here
int b=20; \\ cannot declare here
}
Since C++11, this is fine, you can have default member initialization.
The error is due to missing semicolon after }.
why it has garbage value with b ??
a=b;
b=temp;
temp=a;
Since temp was never initialized before assigning it to b, temp has an indeterminate value.
Any usage will lead to undefined behavior.
Here's a simple Swap struct:
struct Swap
{
int a = 10; // default member initialization
int b = 20; // default member initialization
Swap(int a = 20, int b = 10): a(b), b(a) {}; // swap on initialization
// using member initializer list
};
Swap s;
std::cout << s.a // 20
<< s.b // 10
<< std::endl;
In this example, default member initialization is "obsolete" / "redundant" due to member initializer list.
I would have posted this in the spinroot Bug Reports, but the spinroot forum is not currently accepting new users... If someone out there in charge of that is reading this, please let me in :)
Something very odd is happening when I try to use the select statement. Promela does not allow select() to be called on the field of a struct, so I have to make a temporary variable like this:
typedef someStruct {
int someField;
}
someStruct struct;
inline SetSelect() {
int temp;
select(temp: -1 .. 1);
struct.someField = temp;
}
init{
SetSelect();
}
This runs fine. I tested it and struct.someField is correctly set to either -1, 0, or 1. However, when I try to just put the inlined code straight into the init() process, I get a syntax error. The code looks like this:
typedef someStruct {
int someField;
}
someStruct struct;
init{
int temp;
select(temp: -1 .. 1);
struct.someField = temp;
}
And the error message is:
spin: select_test.pml:9, Error: syntax error saw ''-' = 45'
BUG:
Indeed, it looks like a bug for version 6.4.6 of Spin.
(The bug is fixed in version 6.4.7)
Interestingly, You can make it go away by simply writing temp : instead of temp:.
I suggest you to contact Gerard Holzmann for filing a bug report. I would also mention the fact that select does not seem to work with a struct field, perhaps that can be fixed too (even if it might be by design).
SUGGESTION:
I am not entirely happy of creating an alias variable to get around the issue of the built-in select function with struct fields. Since the implementation of select is rather trivial, as can be found in the docs, I would introduce a novel inline function to replace the built-in select function:
typedef Struct
{
int field;
}
inline my_select (var, lower, upper)
{
var = lower;
do
:: var < upper -> var++;
:: break;
od;
}
init
{
Struct st;
my_select(st.field, -1, 1);
printf("%d\n", st.field);
}