Category "c"

PThreads is not providing a program speedup over serial code

I am creating 2 programs to test the differences in run time of serial matrix multiply vs that of parallel matrix multiply. The parallel code that I have writte

Multithreaded socket programming : sharing variable

Hi I want to implement a ring of sockets .For example IP address 127.0.0.1 listens to 127.0.0.3 and this one listens to 127.0.0.2. They are supposed to share so

Why is my if block not getting executed in my C program?

Why is the if block not executed in the code below? #include <stdio.h> #include <stdlib.h> int main() { printf("--------------------------------

What is cryptic line of code for this statement? [closed]

For example: temp->next = NULL is same as (*temp).next = NULL list->next->next = temp is same as ??

Why is if (2 < 9 < 3) true?

This was a question in my preparation exam: int val = 0; int x = 0; int y = 1; if (x < val < y) printf(" true "); else printf(" false "); Why is

What are the examples of non-ISO practices, which are not found by -pedantic?

https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html : Some users try to use -Wpedantic to check programs for strict ISO C conformance. They soon find that

Recursive Function using MPI library

I am using the recursive function to find determinant of a 5x5 matrix. Although this sounds a trivial problem and can be solved using OpenMP if the dimensions a

How kernel know which driver to be called when we are calling any socket from user-space?

I am using IWD as a wireless daemon in userspace. Driver and firmware are loaded. When the socket is called by IWD using nl80211, it passes to nl80211 and than

What is the most efficient way to copy many files programmatically?

Once upon a time long ago, we had a bash script that works out a list of files that need to be copied based on some criteria (basically like a filtered version

How to divide two unsigned long 64 bit values in x86 assembly and then returning the quotient and remainder to a C program

In a separate C program, I have passed 4 parameters to an x86 ASM program. dividend divisor Quotient pointer Remainder pointer dividend = 0xA divisor = 0x3 Whic

Insert and Delete element on Circular Queue

I'm studying about circular queue in data structure . As you can see from the code below, I try to delete a specific data and insert data on Circular queue. How

Python Ctypes - loading dll throws OSError: [WinError 193] %1 is not a valid Win32 application

I have tried to run an exemple of a python code that gets a function from a library using ctypes. The exemple can be found here. I followed the instruction and

Is there a way to remove all leading and trailing whitespaces of a string in C without the use of external librarys? [closed]

I have been recently trying to make an OS using the C language. The OS shell needs to get the string "ADD" from the string " ADD ". I ne

CMAKE Esp32 using azure iot samples - what to check in into my repository

I am really new to iot/embedded world (I come from the b2b java world). Currently I am starting setting up an ESP32 based project. So far I tried esp-idf Hello

How can I declare a Pointer to a struct in C?

I have learned that pointers can be declared in 3 different ways: int* a; int *b; int * c; I prefer: int* a; While declaring a pointer to a structure, is it c

variably modified 'stack' at file scope [duplicate]

int const a=9; int stack[a]; int main() { return 0; } The above code gives an error:variably modified 'stack' at file scope But when I

Round 37.1-28.75 float calculation correctly to 8.4 instead of 8.3

I have problem with floating point rounding. I want to calculate floating point numbers and round them to (given) N decimals. In this example I want to round to

memory bandwidth for many channels x86 systems

I'm testing the memory bandwidth on a desktop and a server. Sklyake desktop 4 cores/8 hardware threads Skylake server Xeon 8168 dual socket 48 cores (24 per so

Strange warning when calling sprintf with .* width specifier

For the following code: https://godbolt.org/z/WcGf9hEs3 #include <stdio.h> int main() { char temp_buffer[8]; double val = 25.3; sprint

Yacc generated C file sccsid warning supression

I am working on a legacy project that uses yacc - 1.9 20130304. The generated .c files contain the sccsid string (from the skeleton.c): #ifndef lint static cons