I have a struct (small instance so not using code brackets )
struct random {
int a;
int b;
}example;
What i am trying is
example={0,0};
and it gives an error how to initialize all the entries within a struct to zero? In the above example i have used integers but what if they are some other data structure for example another structure?
Following is the way I saw a variable initialized in C
Code:
static const unsigned int rtl8139_rx_config =
RxCfgRcv64K |
(RX_FIFO_THRESH << RxCfgFIFOShift) |
(RX_DMA_BURST << RxCfgDMAShift);
on following link
[URL]
I have initialized variables in past but above initialization I could not understand what is it?
I am using semaphore.h I declared a variable of type sem_t. I am able to use the variable without even calling sem_init or sem_open, and it is working properly.if the variable is automatically assigned some value? Also would I run into any trouble doing so?
View 1 Replies View RelatedI'm making script for automated compiling of one program which would output builds optimized for many architectures. For clearancy, I do each build in it's own catalogue and list of builds with their respective catalogues would be stored as array. I'm using this guide as reference. It describes making array as naming a variable with additional brackets denoting it's position in array.
In my code, it looks exactly like this:
Code:
mtune[1]="build/mtune/athlon"
mtune[2]="build/mtune/athlon-4"
mtune[3]="build/mtune/athlon-mp"
[code]....
But upon invoking $mtune or any $mtune[x] variable, output is blank, like the variable(s) were never initialized. What am I doing wrong?
I am having a problem initializing the Pmw megawidgets for Python 2.6.I have Pmw_1_3 loaded in the site-packages directory.
View 1 Replies View RelatedI am having the following error while executing script and initialing my application
./ss.sh: line 1: kk.sh: command not found
./ss.sh: line 2: mon.exe: command not found
Can somebody assist ASAP.
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 made 2 files which are different from the program above one is temp1.h and another is temp2.c to understand how extern is used. So here is temp1.h
Code:
#include<stdlib.h>
typedef struct node * bond;
extern int jk;
and temp2.c is
Code:
#include<stdio.h>
#include<temp1.h>
struct node {
int data;
[code]...
I had declared jk in temp1.h as an extern int so why can I not initialize it in temp2.c?
Kernel 2.6.21.5, slackware 12.0 as 2.17 [I am speaking here about 80x86 processors, with their segment registers SS, DS, CS, ES.] In a source file for as, I wrote
Code:
.section _STACK
.rept 4096
.word 0
.endr
Now, in the .text section, I want to initialize SS, the stack segment, to point to the _STACK section. In other assemblers, there was a special section for the stack, and the linker cared about initializing SS. Here I use a common section for the stack. For a segment such as DS, I could write
mov ax,_DATA
mov ds,ax
But I don't think mov ax,_STACK would do with as/ls.how do I initialize SS?
While initializing my application the following errors is returned:
Bash profile for the user is as follows:
initializing a branch in one Launchpad project on multiple computers, or even upon reinstalling an OS? I know I sure haven't.
View 1 Replies View RelatedHow do you malloc a struct in C? I have a structure of the form:
Code:
typedef struct child_req_to_parent
{
[code]...
I am learning Kernel Programming these days I came across a structure
Code:
static DEFINE_PCI_DEVICE_TABLE(rtl8139_pci_tbl) = {
{0x10ec, 0x8139, PCI_ANY_ID, PCI_ANY_ID, 0, 0, RTL8139 },
{0x10ec, 0x8138, PCI_ANY_ID, PCI_ANY_ID, 0, 0, RTL8139 },
{0x1113, 0x1211, PCI_ANY_ID, PCI_ANY_ID, 0, 0, RTL8139 },
{0x1500, 0x1360, PCI_ANY_ID, PCI_ANY_ID, 0, 0, RTL8139 },
[Code]...
I have started learning C and am following Ivor Horton's "Beginning C - From Novice to Professional". I've noticed that in the book the structure of the main function is:
int main (void) however on the internet I found a lot of cases: void main (void)Which one is preferred and why?
I am implementing c program to access ext3 file system's metadata. I want to know how to access members of the in-memory superblock structure. I am able access on-disk ext3_super_block structure but dont know how to access in- memory structure and its members.
View 1 Replies View RelatedI have a mxn matric (which is my simplified way of saying it is RAM with bytes on it) Some of the locations on this metric is filled with some data and some places are empty. The mxn are very big numbers in size. I am trying to make a program so that if a system call wants to write some thing on empty locations on this mxn metric it should be able to do so without any problem. The thing which I want to understand or logic of a data structure is what data structure do you people feel should I be maintaining so that I can allocate the requested space immediately from the above mxn matric when some system call requests for some (k) number of locations from above metrics.
The logic initially I thought was to maintain a hashtable
1bytes requested----------> location 1,location 2,location 3.........location n
2bytes requested----------> location 1,location 2,location 3.........location n
3bytes requested----------> location 1,location 2,location 3.........location n
[code]....
but the problem with above logic is size of the pointers where I will be writing this problem is unsigned 64 byte.So to know location of one free byte if I am maintaining one pointer of type u64 this is not a feasible solution.
I wanted to implement a graph.By graph I mean to say that I am writing programs for BFS,DFS and other such stuff and want to see them in action. For this I started writing a program.The first entry point is to define a graph. I took a pen and paper and made a graph. Now to be able to code this in C.I defined a structure but I am finding problem in defining this structure. I looked into Google and came across incidence list and adjacency list representation [URL] after understanding that I am not able to understand how do I define my structure that would be a node in graph. Here is what my graph looks like
Quote:
|-----------31
| |
| 2---4---6---8
| |
[code]....
I am currently writing a program using raw sockets. This program is used to send out ARP reply frames. The problem that I have is that I do not seem to be able to fill out a structure that is pointing to part of a character array.
Code:
struct eth_header *eth;
struct arp_header *arp;
char buf[8];
eth = (struct eth_header *)buf;
arp = (struct arp_header *)(buf+sizeof(struct arp_header));
Whilst I can fill out the variables of eth, I cannot fill out the variables of arp. If I fill them out and then send the contents of the array using send to, only the first structure (the ethernet header) is sent out. The rest of the data appears to be the original junk data in the array. I have checked the address of the structure pointer and it is pointing to the right place in the array. If I write a raw sockets program that uses an IP header struct and TCP header struct I can point these into the array and write to both of them without any issues.
The difference here is that the call to socket is different:
Code:
/* For ethernet */
fd = socket(AF_INET, SOCK_PACKET, htons(ETH_P_ARP));
/* For IP */
fd = socket(AF_INET, SOCK_RAW, IPPROTO_RAW);
If I just create one structure containing all of the variables needed this gets around the issue, however, I would like to know what I am doing wrong in the first instance.
I have added new member "i_mymember" to inode on-disk structure in ext3_fs.h file and tried to access this in userspace program, but gives me error that "error: �struct ext3_inode� has no member named �i_mymember� "
I have compiled my kernel source code.
why this error is coming ...?
Options:A double linked list with fixed size character arrays. New nodes will be added when previous ones get filled. Dynamic arrays using realloc(). Linked list has the disadvantage of not having an O(1) search like an array but I think using realloc() will be more dangerous since it moves the whole block to a new location and if the new location is not big enough to hold the whole block, realloc fails !! this case will not occur with the linked list since its nodes are scattered.
View 14 Replies View RelatedI am writting a program that reads a text file (music.txt) & stores it in a Data Structure. I am a novice learning over the internet so I this is something I have never done. How do I do this?
Quote:
Write a program that reads the data from the music.txt file and store it in a data structure. To implement this data structure you must use an array of songs and each song must be represented by a struct with appropriate fields. So far all I can do is open to file to read it (very simple I know) but so far is it correct?
Code:
#include <iostream>
#include <fstream>
#include <strstream>
[code]....
I'm using ubuntu9.10 (x86_64) and have some code,
Code:
void show_utmp(struct utmp* ent)
{
time_t tmp;
if (ent->ut_type != USER_PROCESS)
return;
[Code]....
How can I disable structure alignment feature of gcc using command-line options ?I recently migrated to 64-bit OS, and doubt that I might be experiencing a structure alignment problem due to the new 64-bit architecture.I checked the sizes of the same C-style struct in both x86 and x86_64, and found out that they appear to be different by 20 bytes.I am not sure if this is due to structure alignment or the differences in data type lengths between two platforms.Hence, I will first disable the structure alignment feature, and then check the struct sizes again.
View 3 Replies View Relatedtelling the exact macro name and location, by which I can gain control over the following kernel base level structure
1. strct super_block of Virtual File System, for super block object.
2. strct inode for inode ofject of VFS.
3 file structure for file object of VFS.
in addition to these if you know location to access other kernel structure.Please let me know.My main objective is to get the access to the structure pointer of these structure by which i can have access over the individual fields o these structure.
I'm having problems with compiling recursive Makefiles in my directory structure:
My folder layout is:
top/|- one/|- one.c (With main function)|- zero.c|- two/|- two.cin my top folder the make file looks like:
Code:
MAKE_DIRECTORIES = one two
.PHONY: all
all: $(MAKE_DIRECTORIES)
.PHONY: $(MAKE_DIRECTORIES)
$(MAKE_DIRECTORIES):
@echo $@
$(MAKE) --directory=$@
in my one and two folder I have the following Makefile:
Code:
.PHONE: all
all:
@echo $@
$(CC) $(CFLAGS) *.c
But when I compile it from top folder: make
I get following output:
Code:
one
two
Which states that directory statement by echo in main Makefile is ok but the files are not compiled in one and two.
I am trying to create a simple bash script to rsync some folders within a directory stucture. I am using wild cards, in the rsync source directory structure, but my command always fails. I believe it is the way I am using wild cards within my for loop. Here is my command ;
Code:
for seq in `cat test.txt` ; do rsync -nvP /folder/folder/folder/folder/folder/**/$seq /folder/folder/folder/ ; done This always fails, where if I do a ls to the destination, to test the path, it always works.
Has any one ever come across a book on Linux programming which explains a Library structure in depth?
View 3 Replies View Related[Code]....
if the address of stWndClass is 403000h, WHY it would be compile as mov eax,[esi+403004] and the first one would be mov eax,[esi+4]? I know how to get the values 403004h and 4,but do not know why.
I want to read an ftp site [URL]...and download the sub-directory structure and ONLY the tagfiles to the local directory.
FROM THIS:
Code:
slackware
+--a
| |aaa_base-12.2.0-noarch-1.tgz
| |aaa_base-12.2.0-noarch-1.tgz.asc
[code]....
I tried wget + grep but that didn't work too well.
Does anyone know of a C Language Data Structure Tutorial? I have not been able to find anything much to speak of myself.
View 4 Replies View Related