objective-c - 如何将 STDOUT 重定向到 NSTextView？

Question

有人可以告诉我如何将 Stdout 重定向到 NSTextView 吗？

NSLog打印的信息是否属于std？

谢谢

Answer 1

下面的代码使用 dup2 将标准输出插入到 NSPipe 对象的写入端。使用 GCD 调度源观察读取端，它从管道读取数据并将其附加到 TextView 。

NSPipe* pipe = [NSPipe pipe];
NSFileHandle* pipeReadHandle = [pipe fileHandleForReading];
dup2([[pipe fileHandleForWriting] fileDescriptor], fileno(stdout));
dispatch_source_t source = dispatch_source_create(DISPATCH_SOURCE_TYPE_READ, [pipeReadHandle fileDescriptor], 0, dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0));
dispatch_source_set_event_handler(source, ^{
    void* data = malloc(4096);
    ssize_t readResult = 0;
    do
    {
        errno = 0;
        readResult = read([pipeReadHandle fileDescriptor], data, 4096);
    } while (readResult == -1 && errno == EINTR);
    if (readResult > 0)
    {
        //AppKit UI should only be updated from the main thread
        dispatch_async(dispatch_get_main_queue(),^{
            NSString* stdOutString = [[NSString alloc] initWithBytesNoCopy:data length:readResult encoding:NSUTF8StringEncoding freeWhenDone:YES];
            NSAttributedString* stdOutAttributedString = [[NSAttributedString alloc] initWithString:stdOutString];
            [self.logView.textStorage appendAttributedString:stdOutAttributedString];
        });
    }
    else{free(data);}
});
dispatch_resume(source);

NSLog(@"...") 虽然不会输出到 stdout - 它会打印到 stderr。如果您想将其重定向到您的 TextView ，请更改

dup2([[pipe fileHandleForWriting] fileDescriptor], fileno(stdout));

到

dup2([[pipe fileHandleForWriting] fileDescriptor], fileno(stderr));