c

Multiple sendto() using UDP socket

Hi, I have a network software which uses UDP to communicate with other instances of the same program. For different reasons, I must use UDP here. I recently had problems sending huge ammounts of data over UDP and had to implement a fragmentation system to split my messages into small data chunks. So far, it worked well but I now encoun...

writing into a file in c.

i have an char array b[20] which i want to write into a file . After every iteration the value of b[20] changes , so i would like to write the string in each line of the file in each iteration . So how can i change a new line in a file and also put in a array of character? ...

Recognizing Tail-recursive functions with Flex+Bison and convert code to an Iterative form

I'm writing a calculator with an ability to accept new function definitions. Being aware of the need of newbies to try recursive functions such as Fibonacci, I would like my calculator to be able to recognize Tail-recursive functions with Flex + Bison and convert code to an Iterative form. I'm using Flex & Bison to do the job. If you hav...

How can I speed-up this loop (in C)?

Hi! I'm trying to parallelize a convolution function in C. Here's the original function which convolves two arrays of 64-bit floats: void convolve(const Float64 *in1, UInt32 in1Len, const Float64 *in2, UInt32 in2Len, Float64 *results) { UInt32 i, j; for (i = 0; i < in1Len;...

C or Ada for engineering computations?

Hi,as an engineer I currently use C to write programs dealing with numerical methods. I like C as it's very fast. I don't want to move to C++ and I have been reading a bit about Ada which has some very good sides. I believe that much of the software in big industries have been or more correctly were written in Ada. I would like to know...

segmentation fault in file operations in c

#include<stdio.h> /* this is a lexer which recognizes constants , variables ,symbols, identifiers , functions , comments and also header files . It stores the lexemes in 3 different files . One file contains all the headers and the comments . Another file will contain all the variables , another will contain all the symbols. */ int mai...

Making global static variables multithread safe

I have global static variables in a C library, which generate exceptions in a multithread run. I need to make them safe in some way (i.e., each thread should relate to a different instance of these variables). Any recommended methods? ...

Error in a C code while trying to remove whitespace

this code is the base of lexer , and it does the basic operation of removing the whitespaces from a source file and rewrites it into another file with each word in separate lines . But i am not able to understand why the file lext.txt not getting updated? #include<stdio.h> /* this is a lexer which recognizes constants , variables ,sym...

Program execution stop at scanf???

main.c (with all the headers like stdio, stdlib, etc): int main() { int input; while(1) { printf("\n"); printf("\n1. Add new node"); printf("\n2. Delete existing node"); printf("\n3. Print all data"); printf("\n4. Exit"); printf("Enter your option -> "); scanf("%d", &input); string key = ""; string ...

Why would I get a bus error or segmentation fault when calling free() normally?

I have a very simple test program, running on Solaris 5.8: #include <stdio.h> #include <stdlib.h> int main(void) { char *paths; paths = getenv("PATH"); printf("Paths: %s\n", paths); free(paths); // this causes a bus error return 0; } If I don't call free() at the end, it displays the message fine and exits. If I...

Can printf change its parameters??

EDIT: complete code with main is here http://codepad.org/79aLzj2H and once again this is were the weird behavious is happening for (i = 0; i<tab_size; i++) { //CORRECT OUTPUT printf("%s\n", tableau[i].capitale); printf("%s\n", tableau[i].pays); printf("%s\n", tableau[i].commentaire); //WRONG OUTPUT //printf("%s --- %s --- %...

Suggestions for duplicate file finder algorithm (using C)

Hello, I wanted to write a program that test if two files are duplicates (have exactly the same content). First I test if the files have the same sizes, and if they have i start to compare their contents. My first idea, was to "split" the files into fixed size blocks, then start a thread for every block, fseek to startup character of ev...

"assignment makes integer from pointer without a cast " warning in c

#include<stdio.h> /* this is a lexer which recognizes constants , variables ,symbols, identifiers , functions , comments and also header files . It stores the lexemes in 3 different files . One file contains all the headers and the comments . Another file will contain all the variables , another will contain all the symbols. */ int mai...

incompatible declaration in built in function malloc and incompatible types in assignment error in c

char char* c[30]; c = (char*) malloc(30*sizeof(char) ); How does this give an incompatible declaration in built in function warning and and incompatible types in assignment error in the line where i have declared malloc . According to the syntax of malloc , i shouldnt have any error ...

gcc, UTF-8 and limits.h

My OS is Debian, my default locale is UTF-8 and my compiler is gcc. By default CHAR_BIT in limits.h is 8 which is ok for ASCII because in ASCII 1 char = 8 bits. But since I am using UTF-8, chars can be up to 32 bits which contradicts the CHAR_BIT default value of 8. If I modify CHAR_BIT to 32 in limits.h to better suit UTF-8, what do I ...

Write a signal handler to catch SIGSEGV

Hi all, I want to write a signal handler to catch SIGSEGV. First , I would protect a block of memory for read or writes using char *buffer; char *p; char a; int pagesize = 4096; " mprotect(buffer,pagesize,PROT_NONE) " What this will do is , it will protect the memory starting from buffer till pagesize for any reads or writes. ...

Optional read from STDIN in C

My application is basically a shell which expects an input of type cmd [x], where cmd is constant and x is optional. So cmd 1 is legal as well as cmd by itself - then I assume a default parameter for x. I am doing this: char cmd[64]; scanf("%s", cmd); int arg; scanf("%d", &arg); // but this should be optional How can I read the integ...

SOAP library in C

I am looking for a SOAP Library for C. I know there is gSOAP. What other options do I have? ...

Parse values from a text file in C

Possible Duplicate: Parsing text in C Say I have written to a text file in this format: key1/value1 key2/value2 akey/withavalue anotherkey/withanothervalue I have a linked list like: struct Node { char *key; char *value; struct Node *next; }; to hold the values. How would I read key1 and value1? I was thinkin...

python tracing a segmentation fault

Hi, I'm developing C extensions from python ad I obtain some segfaults (inevitable during the development...). I'm searching a way to display at which line of code the segfault happens (an idea is like tracing every single line of code), how I can do that? ...