I've been using the following code to create various struct, but only give people outside of the C file a pointer to it. (Yes, I know that they could potentially mess around with it, so it's not entirely like the private keyword in Java, but that's okay with me). Anyway, I've been using the following code, and I looked at it today, and...
Hi all, This a follow up on my previous question. link here. My question is: Let's say I have the following code.. char* buf = (char*) malloc(1024); ... for(; i<20; i++) { if(read(fd, buf, 1024) == -1) { // read off a file and store in buffer perror("read failed"); return 1; } ... } free(buf); what...
Hi, I have following situation (unix) : x is a long and has value 300 y is a long and has value 50000 if (x <= y) printf("Correct."); if (x > y) printf("Ouch."); Now I always get "Ouch". That means the program keeps telling me that 300 is greater than 50000! It only works again when I do if ((int)x <=(int) y) printf("Correct."); ...
I was reading up about bypassing objective-c's messaging to gain performance (irrelevant to this specific question) when i found an interesting bit of code: #import <Cocoa/Cocoa.h> @interface Fib : NSObject { } - (long long) cFib: (NSUInteger) number; @end @implementation Fib // c implementation of fib long long cFibIMP(NSUInteger ...
Hi I'm trying to use libssl to get some EMSA_PSS_ENCODING through the function RSA_padding_add_PKCS1_type1 in libssl, but I can't find nor docs nor solutions, so this is the example code I've written: #include <stdio.h> #include <stdlib.h> #include <string.h> #include <openssl/rsa.h> #include <openssl/err.h> FILE *error_file; int main...
Hello, I need your advice on this piece of code: the table fields options[0], options[1] etc... doesn't seem to be freed correctly. Thanks for your answers int main() { .... char **options; options = generate_fields(user_input); for(i = 0; i < sizeof(options) / sizeof(options[0]); i++) { free(options[i]); options[i] = N...
I have came across the following code, and being a C beginner, I came here for your help. This function is from a c implmentation of a queue. Bool queuePut(Queue *q, char c) { void beep(); if (queueFull(q)) { beep(); return false; } //do stuff return true; } So, I am getting a strange erro...
I'm learning to use raw sockets, and im trying to prase out the tcp header data, but i can't seem to figure out what res1, ece, and cwr are. Through my networking book and google i know what the rest stand for, but can't seem to find anything on those three. Below is the tcphdr struct in my includes area. Ive commented the parts a bit ...
I'm trying to solve exercise from K it's about reading directories. This task is system dependent because it uses system calls. In the book example authors say that their example is written for Version 7 and System V UNIX systems and that they used the directory information in the header < sys/dir.h>, which looks like this: #ifndef DIRS...
I've been looking at Boost and various other C++ libraries. The vast majority of Boost is implemented in header files. My question is: under what conditions do you do a header-only implementation (like Boost) or also include a .cpp file? ...
I have a server that connects to multiple clients using TCP/IP connections, using C in Unix. Since it won't have more than 20 connections at a time, I figured I would use a thread per connection/socket. But the problem is writing to the sockets as I'll be sending user prompted msgs to clients. Once each socket is handled by a thread, how...
As demonstrated in this answer I recently posted, I seem to be confused about the utility (or lack thereof) of volatile in multi-threaded programming contexts. My understanding is this: any time a variable may be changed outside the flow of control of a piece of code accessing it, that variable should be declared to be volatile. Signal...
How can I implement signal Handling for Ctrl-C and Ctrl-D in C....So If Ctrl-C is pressed then the program will ignore and try to get the input from the user again...If Ctrl-D is pressed then the program will terminate... My program follows: int main(){ char msg[400]; while(1){ printf("Enter: "); fgets(msg,400,stdin); prin...
I've written a C program that works when I pipe data into my program using stdin like: gunzip -c IN.gz|./a.out If I want to run my program on a list of files I can do something like: for i `cat list.txt` do gunzip -c $i |./a.out done But this will start my program 'number of files' times. I'm interested in piping all the files in...
I'm trying to make a RLE (Run-Length Encoder) Programme just for characters. I read the way it works on notes on net. And I tried to fix my code! Regardless I think that the steps of code are right, the code doesnt work! It appears some strange 'Z' as it runs. I really can't find what;s wrong! Could you please give me a piece of advice?...
Hi, everyone. I am debugging a python module with homemade c extensions. The output seems correct when I print it with 'p' in pdb. But if I use a normal print statement or pickle it, the output is wrong. What could be causing pdb to show different values than normal execution? I can even step to the print statement in debug mode, an...
HI...I'm making a project and the program receives info about people, how can i save all info to XML? ...
Is it possible to access the "errno" variable in C# when P/Invoking? This is similar to Win32 GetLastError(). ...
Hi, I have a simple gateway listener which generates a log at the screen output via printf. I would like to record it so I can insert it in a mysql table. printf("\nPacket received!! Decoding..."); I wonder if there is any fast way to do this is C. In case there is, could I get both outputs at the same time? Thanks ...
I've run into the need to be able refer to a directory by path given its file descriptor in Linux. The path doesn't have to be canonical, it just has to be functional so that I can pass it to other functions. So, taking the same parameters as passed to a function like fstatat(), I need to be able to call a function like getxattr() which ...