1 #include <assert.h> 2 #include <stdio.h> 3 #include <fcntl.h> 4 #include <unistd.h> 5 #include <uv.h> 6 7 void on_read(uv_fs_t *req); 8 9 uv_fs_t open_req; 10 uv_fs_t read_req; 11 uv_fs_t write_req; 12 13 static char buffer[1024]; 14 15 static uv_buf_t iov; 16 17 void on_write(uv_fs_t *req) { 18 if (req->result < 0) { 19 fprintf(stderr, "Write error: %s\n", uv_strerror((int)req->result)); 20 } 21 else { 22 uv_fs_read(uv_default_loop(), &read_req, open_req.result, &iov, 1, -1, on_read); 23 } 24 } 25 26 void on_read(uv_fs_t *req) { 27 if (req->result < 0) { 28 fprintf(stderr, "Read error: %s\n", uv_strerror(req->result)); 29 } 30 else if (req->result == 0) { 31 uv_fs_t close_req; 32 // synchronous 33 uv_fs_close(uv_default_loop(), &close_req, open_req.result, NULL); 34 } 35 else if (req->result > 0) { 36 iov.len = req->result; 37 uv_fs_write(uv_default_loop(), &write_req, 1, &iov, 1, -1, on_write); 38 } 39 } 40 41 void on_open(uv_fs_t *req) { 42 // The request passed to the callback is the same as the one the call setup 43 // function was passed. 44 assert(req == &open_req); 45 if (req->result >= 0) { 46 iov = uv_buf_init(buffer, sizeof(buffer)); 47 uv_fs_read(uv_default_loop(), &read_req, req->result, 48 &iov, 1, -1, on_read); 49 } 50 else { 51 fprintf(stderr, "error opening file: %s\n", uv_strerror((int)req->result)); 52 } 53 } 54 55 int main(int argc, char **argv) { 56 uv_fs_open(uv_default_loop(), &open_req, argv[1], O_RDONLY, 0, on_open); 57 uv_run(uv_default_loop(), UV_RUN_DEFAULT); 58 59 uv_fs_req_cleanup(&open_req); 60 uv_fs_req_cleanup(&read_req); 61 uv_fs_req_cleanup(&write_req); 62 return 0; 63 } 64