1 #include <assert.h> 2 #include <stdio.h> 3 #include <fcntl.h> 4 #include <uv.h> 5 6 void on_read(uv_fs_t *req); 7 8 uv_fs_t open_req; 9 uv_fs_t read_req; 10 uv_fs_t write_req; 11 12 static char buffer[1024]; 13 14 static uv_buf_t iov; 15 16 void on_write(uv_fs_t *req) { 17 if (req->result < 0) { 18 fprintf(stderr, "Write error: %s\n", uv_strerror((int)req->result)); 19 } 20 else { 21 uv_fs_read(uv_default_loop(), &read_req, open_req.result, &iov, 1, -1, on_read); 22 } 23 } 24 25 void on_read(uv_fs_t *req) { 26 if (req->result < 0) { 27 fprintf(stderr, "Read error: %s\n", uv_strerror(req->result)); 28 } 29 else if (req->result == 0) { 30 uv_fs_t close_req; 31 // synchronous 32 uv_fs_close(uv_default_loop(), &close_req, open_req.result, NULL); 33 } 34 else if (req->result > 0) { 35 iov.len = req->result; 36 uv_fs_write(uv_default_loop(), &write_req, 1, &iov, 1, -1, on_write); 37 } 38 } 39 40 void on_open(uv_fs_t *req) { 41 // The request passed to the callback is the same as the one the call setup 42 // function was passed. 43 assert(req == &open_req); 44 if (req->result >= 0) { 45 iov = uv_buf_init(buffer, sizeof(buffer)); 46 uv_fs_read(uv_default_loop(), &read_req, req->result, 47 &iov, 1, -1, on_read); 48 } 49 else { 50 fprintf(stderr, "error opening file: %s\n", uv_strerror((int)req->result)); 51 } 52 } 53 54 int main(int argc, char **argv) { 55 uv_fs_open(uv_default_loop(), &open_req, argv[1], O_RDONLY, 0, on_open); 56 uv_run(uv_default_loop(), UV_RUN_DEFAULT); 57 58 uv_fs_req_cleanup(&open_req); 59 uv_fs_req_cleanup(&read_req); 60 uv_fs_req_cleanup(&write_req); 61 return 0; 62 } 63