Closed Christian-health closed 6 years ago
var fs = require('fs');
function openAndWriteToSystemLog(writeBuffer, callback){
fs.open('./my_file', 'a', function opened(err, fd) {
if (err) { return callback(err); }
function notifyError(err) {
fs.close(fd, function() { //如果打开文件发生了异常,那么【关闭文件描述符】
callback(err);
});
}
var bufferOffset = 0,
bufferLength = writeBuffer.length,
filePosition = null;
fs.write( fd, writeBuffer, bufferOffset, bufferLength, filePosition,
function wrote(err, written) {
if (err) { return notifyError(err); }
fs.close(fd, function() { //如果完成了文件的写入,那么【关闭文件描述符】
callback(err);
});
}
);
});
}
openAndWriteToSystemLog(
new Buffer('writing this string'),
function done(err) {
if (err) {
console.log("error while opening and writing:", err.message);
return;
}
console.log('All done with no errors');
}
);
8.2.3 节 6.4节 5.4.5节
第五章
代码1:
代码2
没看懂的地方: 电子书:57 59页