解决方法
下面的代码使用dup2将stdout插入NSPipe对象的写端.使用GCD调度源观察读取端,该源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],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(@“…”)不输出到stdout – 它打印到stderr.如果要将其重定向到文本视图,请更改
dup2([[pipe fileHandleForWriting] fileDescriptor],fileno(stdout));
至
dup2([[pipe fileHandleForWriting] fileDescriptor],fileno(stderr));
