Programming :: Sizeof Struct With Function Pointers As A Member?
Jul 2, 2010I following structure
typedef struct
{
[code]...
I following structure
typedef struct
{
[code]...
is there any problem that might rise by by having a vector as a member of struct in c++ as follows.ex.
struct A
{
int a;
[code]...
Is it possible to create a global struct variable with predefined member values?Only one instance of that struct is ever needed.
View 1 Replies View Relatedlets look at code in C
Code:
#include <stdio.h>
#include <stdlib.h>
[code]...
int GetTime(struct timeval tv)
{
gettimeofday(&tv, NULL)
printf("%d
", tv.tv_sec); /* here is the right value */
return 0;
}
[Code]....
What happend? struct timeval has a self timer?
i'm a bit stuck playing with the following class setup for glut. The actual issue is with the function pointers.Basically the following code is the opengl redbook cube example slightly modified.
View 2 Replies View RelatedI need to call functions that match an input string (if input str = "func1", call func1), so I have this:
Code:
#include <stdio.h>
#include <string.h>
void function_a(void) { printf("Function A
"); }
[Code].....
In the above example, the functions take no input arguments. Can they take a different number of arguments, for example, function_a(int), function_c(int, int), function_e(int, char, int)? How can I do that?
I'm venturing into the world of OpenGL, but in the process of writing my graphics library I ran into a problem... My code is:
Code:
#include <stdio.h>
#include <stdlib.h>
[code]...
I have an old C application in which i am trying to include some STL cointainers. When i use the STL container alone it works fine, but when i include it into a C struct i have segmentation faults errors. I know that it is not a good idea to mix C and C++. Considering this code:
Code:
typedef struct{
int shmid;
...
APPLSPACETYPE applSpace;
[code]...
and how to make a malloc for this issue; something like :
Code:
mem->applSpace.rData.completeGroups2zeroGroup=(map_completeGroups2zeroGroup_type *)malloc((sizeof(map_completeGroups2zeroGroup_type)+1)* sizeof(char ));
I wonder why arrays in the C programming language are pointers to the first element of the array, not the first element of the array itself?
View 14 Replies View RelatedIs is possible to use a class inside a struct? I keep getting segmentation fault with this code:
Code:
struct my_struct {
unsigned count;
std::string msg;
[code]....
I have been spending time (starting yesterday) reverse-engineering GTK+ to get my programming skills up. I came across a struct in the headers (_GtkArg, which was then typedeffed into GtkArg) that includes a union in it that has pretty much the same properties as a struct. Then, there was a struct inside the union.
I'm confused. Just what is the difference between a union and a struct?
P.S. I am using GTK's native C programming language.
How do we allocate memory of struct? what i did was
Code:
int main()
struct amp
{
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cout <<"The size of 'struct' is"<< sizeof(struct amp)<<"and it is located at"<<struct amp*s = malloc(sizeof(struct amp))<<endl;
it gives me an error---
In funtion 'int main()':
error: expected primary-expression before 'struct'
error: expected ';' before 'struct'
For a work project, I've got a bunch of python code from about a year ago that controls the movement of our EVI-D30 camera over a ttyUSB connection. It used to work fine on a 32-bit Fedora box, but recently we moved our whole project over to a 64-bit Gentoo server, and the same code seems to be worthless on the new platform. I didn't write the code, so I'm have trouble figuring out how to fix it. Error messages usually look like this:
Code:
File "./CameraController.py", line 172, in pan
turn_callback(cmdStruct[0], cmdStruct[1])
File "./CameraController.py", line 147, in turn_callback
cameras[camera].TiltUp()
[code]....
I having a nested structures which are referenced with pointer variables :
example :
typedef struct {
int a ;
char *b ;
int *c ;
}EXP2 ;
[Code]...
While trying to access the value of sv.exp2->a it throws segmentation fault error.How to acess this variable ??
I have what should be a relatively simple program (fadec.c) that maps a struct from an included header file (fadec.h) to a shared memory region, but Im struggling accessing members in the struct from the pointer returned by shmat. Ultimately, I want to access members in the shared memory structure with a globally declared version of the struct, shm__. Not only do I not know how to accomplish that, but I cant even seem to access members of the shared struct directly from the pointer itself (compiler complains about dereferencing pointer to incomplete type). Im at a loss and could use another set of eyes if you guys dont mind taking a gander:
Compile Errors:
tony-pc:/cygdrive/p/test> cc -o fadec fadec.c
fadec.c: In function 'main':
fadec.c:30: error: dereferencing pointer to incomplete type
fadec.c:31: error: dereferencing pointer to incomplete type
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i'm practicing in very basic c programs using the gcc compiler.I found that when i create two variables let's say
Code:
int a,b and Code: a=15;
b=3;
a=b;
b--;
then a equals 2.I thought that this isn't normal in C isn't it?I haven't had the time to read the gcc documentation yet...so i think it has something to do with my compiler's default settings.I use the
Code: gcc filename.c -o filename command to compile
Are all variables defined like pointers?
So the place where I'm having a problem is here:
Code:
typedef struct {
void **Mem_Chunk;
[code]...
What is the difference between *ptr++ and (*ptr)++. In my opinion the terminology is all over the place so if you could give an example it would be better.
View 8 Replies View RelatedI am getting the following error:'auto_ptr' is not a member of 'std'This was working fine in gcc version 4.1.2 20080704 (Red Hat 4.1.2-48).After upgrading to gcc version 4.4.4 (GCC), it is NOT working.
View 2 Replies View RelatedCode:
#include <iostream>
using namespace std;
[code]...
I am doing some Linux kernel programming for my research project. I need to record the timestamp (by using cpuid and rdtsc) when an interrupt handler (top half) is first invoked. Due to the time critical nature of the problem itself, I have to do the timestamping inside the interrupt handler itself (the first operation when the handler is called). However, I understand that tasks that are not so time critical should be deferred to a tasklet function (bottom half) for processing because other interrupts are disabled in a (top-half) interrupt handler. I am currently out of idea on how I can pass the timestamp information that I have obtained in the interrupt handler to the corresponding tasklet function.
View 2 Replies View RelatedI want to read a pressed key or a combination of pressed keys from the keyboard and perform some action afterwords.
e.g.
Ctrl-Alt-F1
Out of ncurses lib. and the termios struct which can be used best for the above purpose and why ?I tried to search on Google, the differences between these two but couldn't get much !
I want to know is there some more efficient way of passing a pointer to a local variable as a parameter to a function in x86 asm? Right now I have to move the base pointer to a temp register, subtract from the register and pass that, like this (assuming a local var at esp-4):
Code:
mov eax, ebp
sub eax, 4
push eax
Is there a better way?
I'm trying to figure out how to code for this specific type of instance - I want to use a hash and have the key be a reference to an array, and not use the key in the standard way of it being a scalar. Basically, I have a large output that I need to process line by line, and rather have access to it as an array than a big block in a scalar. For the big block hash as a scalar I would do -
Code:
foreach $CONTROLLER (<CONTROLLER_LIST>) {
$ALL_DISKS{$CONTROLLER} = `ssh -n <commands>`;
}
Now I know I could take the scalar and split it to another array after the fact like -
Code:
@TEMP_HOLD = split (/s+/,$ALL_DISKS{$CONTROLLER});
How would I code it that I would have access to the key information as an array and not a scalar? I know it needs to be a pointer and we're going to have -> in there somewhere, but not sure how to approach it. Some of the documentaiton I've been reading about referencing I've found a little confusing so far, and trying to figure out how to use them in context of what I'm working on.
I've seen all three uses:
type * pointer
type *pointer
type* pointer
Are these 3 forms essentially the same, i.e., is the spacing as used here a non-factor when declaring pointers?
I am trying to find a way to pull Node Pointers out of the model, for use in other areas of the program. The solution is probably simple but I haven't had any luck finding it.
Model for a QTreeView:
Code:
class testModel : public QAbstractItemModel
{
public:
testModel();
~testModel();
[code]....
I have the most strange problem ever in programming. I fork a process into a parent and a child. In every forked process i declare a pointer, malloc and define a different value for every pointer.When i printf the value and the address guess what? They both have the SAME ADDRESS but DIFFERENT values, as assigned..Here's the portion of my code:
pid = fork ();
switch (pid)
{
[code]....
The code below defines an array of structures in a class. I would like this to be a Static array and then initialize the array in a initialization method. I understand that initialization lists are the way to go but due to the size and complexity of the array I plan on using (the example below is a simple snippet that illustrates the problem) I would like to use the initialization method. However, I cant even get this thing to compile. The error says the reference to the ArrayOfStructs in the initialization routine is undefined.
l_long_Island
P.S. This is the error message
undefined reference to `ClassWithStaticArray::ArrayOfStruts'
class ClassWithStaticArray {
public:
struct IntegerStruct
{
[code]....
I understand that block_device pointer *bd sholuld get initialized. Program should produce initialization error for *bd. Compiler is producing '->'. I am not understanding why?
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