Nare

A low-level asynchronous I/O library for Linux based on io_uring.

Example as documentation

/* gcc -I includes/ src/nare.c examples/open.c -luring && a.out */
#include <fcntl.h>  /* openat constants */
#include <stdio.h>  /* printf, fprintf */
#include <stdlib.h> /* exit */
#include <string.h> /* strerror */

#include "nare.h"   /* Nare functions and types */

#define COMPLETED_NENTRIES 16 /* Can handle until 16 completed operations */
#define SUBMITTED_NENTRIES 8  /* Can handle until 8  submitted operations */

void free_resources(void);
void callback(Nare* nare, ssize_t result, void* user_data);

Nare* nare = NULL;
int main() {
    char* path = "examples/open.c";
    char* msg  = "Hi from Nare!";
    int err = 0;

    nare = Nare_alloc(COMPLETED_NENTRIES, SUBMITTED_NENTRIES); /* Alloc resources */
    if (nare == NULL) {
        perror("Nare_alloc");
        exit(EXIT_FAILURE);
    }

    err = Nare_openat(nare, callback, msg, AT_FDCWD, path, O_RDWR, 0); /* Submit openat. See man openat(2) */
    if (err < 0) {
        fprintf(stderr, "Error: Event loop full.\n"); /* Operations can check if it was submitted */
        exit(EXIT_FAILURE);
    }
    
    err = Nare_loop(nare); /* Start event loop */
    if (err < 0) {
        fprintf(stderr, "Error: Fail to start evento loop: %s\n", strerror(-err)); /* Event loop can fail due system errors */
        exit(EXIT_FAILURE);
    }
    exit(EXIT_SUCCESS);
}

void callback(Nare* nare, ssize_t result, void* user_data) {
    char* msg = user_data;
    int fd = result;
    if (fd < 0) {
        fprintf(stderr, "Error: %s\n", strerror(-fd)); /* IO operations always set result to -errno on error */
        exit(EXIT_FAILURE);
    }
    printf("%s\n", msg);
    Nare_close(nare, NULL, NULL, fd); /* Submit close without callback */
    free_resources(); /* Gracefully exit */
}

void free_resources(void) {
    Nare_free(nare); /* Free resources */
    exit(EXIT_SUCCESS);
}

Licence

Nare (files under src/ and includes/) is licensed in the terms of the Mozilla Public License, v. 2.0, as detailed in the headers of each file. See LICENSE for more details.

Other files are under Public Domain (CC0 1.0 Universal) License. See LICENSE-CC0 for more details.