I've been assigned the task (for work) of working with PCAP for the first time in my life. I've read through the tutorials and have hacked together a real simple capture program which, it turns out, isn't that hard. However, making use of the data is more difficult. My goal is to log incomming and outgoing web service requests. Are t...
I have the following code: int main() { int n = 3, m = 4, a[n][m], i, j, (* p)[m] = a; for (i = 0; i < n; i++) for (j = 0; j < m; j++) a[i][j] = 1; p++; (*p)[2] = 9; return 0; } I have a hard time understanding what p is here, and the consequences of the operations on p in the end. Can someone g...
So I've been digging into how the stdio portion of libc is implemented and I've come across another question. Looking at man setvbuf I see the following: When the first I/O operation occurs on a file, malloc(3) is called, and a buffer is obtained. This makes sense, your program should have a malloc in it for I/O unless you actu...
Hi folks, How can I improve / speed up this frequent function? #include <math.h> #include <stdio.h> #include <stdlib.h> #include <time.h> #define M 10 // This is fixed #define N 8 // This is NOT fixed // Assumptions: 1. x, a, b and c are all arrays of 10 (M). // 2. y and z are all matrices of 8 x 10 (N x M). // Requirem...
Hey all, I have this strange problem with recv(). I'm programming client/server where client send() a message (a structure to be exact) and server recv() it. I am also working with multiple sockets and select(). while(1) { readset = info->read_set; info->copy_set = info->read_set; timeout.tv_sec = 1; timeout.tv_usec =...
I've been reading about OOP in C but I never liked how you can't have private data members like you can in C++. But then it came to my mind that you could create 2 structures. One is defined in the header file and the other is defined in the source file. // ========================================= // in somestruct.h typedef struct { ...
I'm looking at textbooks for an undergraduate course in machine-level programming. If the perfect book existed, this is what it would look like: Uses examples written in C or assembly language, or both. Covers machine-level operations such as two's-complement integer arithmetic, bitwise operations, and floating-point arithmetic. Expla...
Can you please give me some comparison between C compilers especially with respect to optimization? ...
I haven't yet implemented this, I'm still in the thinking stage, but I have to go through a file and replace a certain string with another string. For example, <img src="/images/logo.gif" ... should become <img src="/proxy/www.example.com/images/logo.gif" ... Any advice on how I can approach this? Perhaps there exist some "string r...
I've just started reading C and have a question about a macro. How can I print a 5 byte integer value (that happens to be defined in a macro)? For example: #define MAX 0xdeadbeaf12 int main(){ printf(" 0x %2x \n", MAX); } This code prints adbeaf12 but not deadbeaf12. How do I get all the bytes printed? ...
void someFunc() { int stackInt = 4; someOtherFunc(&stackInt); } Is it the case that stackInt's address space could be reallocated after someFunc ends, making it unsafe to assume that the value passed to someOtherFunc represents the stackInt variable with value 4 that was passed to it? In other words, should I avoid passing sta...
Hi, I am developing a c/c++ program on linux. Can you please tell me if there is any c/c++ library which decodes url? I am looking for libraries which convert "http%3A%2F%2F" to: "http://" or "a+t+%26+t" to "a t & t" Thank you. ...
I've got a function that requires const some_type** as an argument (some_type is a struct, and the function needs a pointer to an array of this type). I declared a local variable of type some_type*, and initialized it. Then I call the function as f(&some_array), and the compiler (gcc) says: error: invalid conversion from ‘some_type**’ t...
Hi I have two threads, the main thread 'A' is responsible for message handling between a number of processes. When thread A gets a buffer full message, it should inform thread B and pass a pointer to the buffer which thread B will then process. When thread B has finished it should inform thread A that it has finished. How do I go abo...
I have two almost similar source code trees, but do not have access to the source code repository so I am stuck with release packages that contain also test reports, documentation, binaries etc. the diff command only support --exclude, but I would like to do something like diff -wbur --include='*.c,*.h' tree1 tree2 I know that this que...
I'm writing small program. Program use data from other software. That other software keep data in Sysbase SQL db. To keep my data I'm using SQLite. ATM it looks like that: I read data from SysbaseSQL (id, art_id, name, ...) and then I write data to sqlite (id, art_id, amount). When I show data, I read from Sysbase (id, art_id, name, ..) ...
I generally have ignored using macros while writing in C but I think I know fundamentals about them. While i was reading the source code of list in linux kernel, i saw something like that: #define LIST_HEAD_INIT(name) { &(name), &(name) } #define LIST_HEAD(name) \ struct list_head name = LIST_HEAD_INIT(name) (You can access the re...
I've got a method: public native void doSomething(ByteBuffer in, ByteBuffer out); Generated by javah C/C++ header of this method is: JNIEXPORT void JNICALL Java__MyClass_doSomething (JNIEnv *, jobject, jobject, jobject, jint, jint); How can I get a data array from jobject (that is a ByteBuffer instance) ? ...
insertion_procedure (int a[], int p [], int N) { int i,j,k; for (i=0; i<=N; i++) p[i] = i; for (i=2; i<=N; i++) { k = p[i]; j = 1; while (a[p[j-1]] > a[k]) {p[j] = p[j-1]; j--} p[j] = k; } } What would be few good test cases for this particular insertion procedure? ...
Hello, typedef enum testCaseId { "TC-HIW-0019" = 0, "TC-HIW-0020", "TC-HIW-0021" } testCaseId; I need my test cases to be represented in enum. In my test function, I need to switch between the test cases like: void testfunc(uint8_t no) { switch(no) { case 0: case 1: default: ...