Command Execution (ns_cmd)

Executing shell commands in standard C usually involves reaching for the system() function or wrestling with popen().

Both approaches are fraught with legacy issues. system() offers absolutely no way to capture the output of the command (it just prints directly to the terminal), and popen() requires manually managing streams, allocating buffers, and parsing raw bytes—often leading to memory leaks or buffer overflows.

The ns_cmd module completely replaces these legacy functions with a modern, memory-safe, and highly ergonomic wrapper around Rust’s std::process::Command.

The NextStd Solution

With ns_cmd, executing a command and capturing its exact output is safe and synchronous.

• Complete Stream Capture: Both stdout and stderr are automatically captured and placed into NextStd’s blazingly fast Small String Optimized (ns_string) structs.
• Exit Codes: The exact exit code of the shell process is captured and returned.
• Smart Routing: Pass either a standard C string literal ("uname -a") or a dynamically built ns_string. The macros figure it out automatically.
• Zero Memory Leaks: Thanks to the ns_autocmd macro, process output structs automatically free their own internal string buffers the moment they go out of scope.

Quick Glance

Here is how simple it is to execute a command, read its output, and clean up the memory—all in four lines of C:

#include <nextstd/ns.h>
#include <nextstd/ns_cmd.h>

int main(void) {
    // 1. Initialize the output struct with the auto-cleanup macro
    ns_autocmd ns_cmd_output out = {0}; 

    // 2. Run the command safely
    ns_cmd_run("uname -a", &out);

    // 3. Use the captured data!
    ns_println("Status: {}", out.exit_code);
    ns_println("Output: {}", out.stdout_data);

    // 4. No free() required. Memory cleans itself up here!
    return 0;
}

Deep Dive

Explore the specific features of the ns_cmd module:

• Running Shell Commands
• Capturing Stdout & Stderr
• Auto-Cleanup (RAII in C)