# C standard library

**[C standard library](https://en.cppreference.com/w/c/header)** is the core set of headers and functions always linked into C programs, providing essential utilities like I/O (`<stdio.h>`), memory management (`<stdlib.h>`), string handling (`<string.h>`), and math operations (`<math.h>`). Headers declare functions and constants; the library implementation lives in `libc.so` (dynamic) or `libc.a` (static).

Modern C lacks advanced data structures (no maps, vectors, or trees), async/threading, and networking—you must implement these yourself or use external libraries.

## Example

This example demonstrates basic C standard library usage with I/O and memory allocation.

```c
// compile: gcc -o stdlib stdlib.c
// run: ./stdlib
// description: use standard library for I/O, memory, and string operations

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main() {
    char *buffer = malloc(50);
    if (!buffer) {
        fprintf(stderr, "Memory allocation failed\n");
        return EXIT_FAILURE;
    }
    
    strcpy(buffer, "Hello from stdlib");
    printf("%s\n", buffer);
    
    free(buffer);
    return EXIT_SUCCESS;
}
```