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Showing posts with the label C++

pthread gets cancelled before releasing locks

 In multithreaded programming using pthreads in C/C++, it's essential to handle thread cancellation correctly, especially when locks are involved. When a thread is canceled before releasing locks, it can lead to resource leaks and potential deadlocks. To avoid this issue, you should follow some best practices: 1. **Use Cancellation Points**: Ensure that your code has well-defined cancellation points where a thread can be safely canceled. These points are locations in your code where it's safe to terminate a thread, such as after releasing locks. 2. **Explicitly Release Locks**: Always explicitly release locks (mutexes) before a thread is canceled. You can use `pthread_mutex_unlock` to release a mutex. Failing to release a lock can lead to deadlock scenarios, where other threads may be unable to acquire the locked resource. 3. **Cancellation Cleanup Handlers**: Consider using cancellation cleanup handlers (`pthread_cleanup_push` and `pthread_cleanup_pop`) to ensure that resource

Ducktape rust to c compiler via assembly

There isn't a project called "Ducktape" that specifically serves as a Rust to C compiler via assembly. However, Rust has the ability to interoperate with C code and can call C functions directly. Here's how you can achieve interoperability between Rust and C, including the use of assembly: 1. **Rust to C Interoperability**:    - Rust has built-in support for calling C functions using the `extern` keyword. You can declare C functions in your Rust code and then call them as if they were regular Rust functions. This means you don't need a separate compiler to convert Rust to C.    ```rust    extern "C" {        fn c_function(arg: i32) -> i32;    }    ```    You can call `c_function` as you would any other Rust function. 2. **Assembly Code Integration**:    - If you want to include assembly code in your project, you can use inline assembly within Rust code. Rust supports inline assembly using the `asm!` macro. You can include assembly snippets directly in

What does setting the timeout to '-1' do for the poll()-function and how do I code a non-blocking scanf()-function?

 In C, setting the timeout to '-1' for the `poll()` function will make it behave as a blocking call, meaning it will wait indefinitely until the file descriptor(s) or events being monitored become ready. On the other hand, if you want to code a non-blocking `scanf()` function in C, you can use a combination of functions to achieve this. The key is to ensure that the program doesn't block while waiting for input. Here's an example of how you can do this using `select()`: ```c #include <stdio.h> #include <stdlib.h> #include <sys/select.h> #include <sys/time.h> #include <sys/types.h> int main() {     fd_set readfds;     struct timeval tv;     int ret;     while (1) {         // Set up the file descriptor set         FD_ZERO(&readfds);         FD_SET(STDIN_FILENO, &readfds);         // Set the timeout to 0 for non-blocking behavior         tv.tv_sec = 0;         tv.tv_usec = 0;         ret = select(STDIN_FILENO + 1, &readfds, NULL,