no_std attribute

custom.css

@@ -19,19 +19,4 @@
 
 .fa-bars{
     font-size: 2em; /* Adjust the size as needed */
-}
-
-
-.footer-content {
-    text-align: center;
-    padding: 20px;
-    background-color: #f8f9fa;
-}
-
-.footer-content .fa-github {
-    margin-right: 10px;
-}
-
-.footer-content img {
-    vertical-align: middle;
 }

src/essentials/no-std.md

@@ -0,0 +1,44 @@
+## What is the purpose of ![no_std]?
+
+The #![no_std] attribute in Rust is used to indicate that a crate does not use the Rust standard library (std). Instead, it relies on the core library (core), which is a subset of the standard library and is available in environments where the full standard library is not available, such as embedded systems or operating system kernels.
+
+## Purpose of #![no_std]
+
+**Embedded Systems**: Many embedded systems do not have the resources to support the full standard library.
+**Operating System Development**: When writing an operating system, you often need to avoid dependencies on the standard library.
+**Custom Environments**: Any environment where the standard library is not available or not desired.
+
+Here’s an example of how you might use #![no_std] in a Rust crate:
+
+```rust
+#![no_std]
+
+extern crate core;
+
+use core::fmt;
+
+struct MyStruct;
+
+impl fmt::Display for MyStruct {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "Hello, no_std!")
+    }
+}
+
+fn main() {
+    let my_struct = MyStruct;
+    println!("{}", my_struct); // This will not work because println! is part of std
+}
+```
+
+## Key Points
+
+**No Standard Library**: The crate does not link to the standard library.
+**Use core**: You can use the core library, which provides essential functionalities like Option, Result, and basic traits.
+**Limited Functionality**: Without the standard library, you lose access to many features like heap allocation, file I/O, and threading.
+
+## Common Use Cases
+
+**Embedded Development**: Writing firmware for microcontrollers.
+**Operating System Kernels**: Developing low-level system software.
+**WASM (WebAssembly)**: Targeting WebAssembly where the standard library is not fully supported.