请问有人能向我展示如何将Stdout重定向到NSTextView吗?
另外,NSLog打印的信息是否属于std?
谢谢
请问有人能向我展示如何将Stdout重定向到NSTextView吗?
另外,NSLog打印的信息是否属于std?
谢谢
dup2
将stdout插入到NSPipe
对象的写入端口。读取端口通过GCD调度源进行观察,该调度源从管道中读取数据并将其附加到文本视图中。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(@"...")
输出的不是 stdout
,而是打印到了 stderr
。如果你想将其重定向到你的文本视图中,请更改dup2([[pipe fileHandleForWriting] fileDescriptor], fileno(stdout));
转化为dup2([[pipe fileHandleForWriting] fileDescriptor], fileno(stderr));
我知道这个问题是关于Objective-C的,但我想发表一篇Swift的答案,以便帮助其他人。
let pipefd = UnsafeMutablePointer<Int32>.allocate(capacity: 8)
pipe(pipefd)
dup2(pipefd[1], fileno(stdout))
// Print something here
let buf = UnsafeMutableRawPointer.allocate(byteCount: 1024, alignment: 0)
read(pipefd[0], buf, 100)
close(pipefd[1])
let output = self.ptrToString(pointer: buf)
if output != "" {
// Do something with output
}
buf.deallocate()
pipefd.deallocate()
func ptrToString (pointer buf: UnsafeMutableRawPointer) -> String {
let filteredArray = Array(UnsafeBufferPointer(start: buf.assumingMemoryBound(to: UInt8.self), count: 1024)).filter { item in
return item != 0
}
return filteredArray
.map { String(UnicodeScalar(UInt8($0))) }
.joined()
.components(separatedBy: "\n")[0]
}
适用于Swift 4
NSError * hala;
NSTask * nettask = [[NSTask alloc] init];
nettask.executableURL = [NSURL URLWithString:@"file:/usr/sbin/networksetup"];
nettask.arguments = [NSArray arrayWithObject:@"-listlocations"];
NSPipe * piper = [NSPipe pipe];
nettask.standardOutput = piper;
NSFileHandle * pipereader = [piper fileHandleForReading];
[nettask launchAndReturnError:&hala];
if (hala) printf ("taskproblem %s\n", hala.description.UTF8String);
[nettask waitUntilExit];
if ([nettask terminationStatus]) printf ("task did not end successfully\n");
else {
NSData * readout = [pipereader readDataToEndOfFileAndReturnError:&hala];
if (hala) printf ("readproblem %s\n", hala.description.UTF8String);
NSString * result = [[NSString alloc] initWithBytes:readout.bytes length:readout.length - 1 encoding:NSASCIIStringEncoding]; //skip trailing \n
}
如果目标仅是处理您的NSLog输出,而不是系统生成的错误日志,则有另一种方法可以实现。以下是一个代码来覆盖NSLog。该代码仅将日志和一些额外信息打印到stderr,而不是通常的NSLog输出,但您可以在HyperLog函数内进行任何适合您需求的更改:
HyperLog.h
#import <Foundation/Foundation.h>
#ifdef HYPER_LOG
#define NSLog(args...) HyperLog(__FILE__,__LINE__,__PRETTY_FUNCTION__,args);
#else
#define NSLog(x...)
#endif
void HyperLog(const char *file, int lineNumber, const char *functionName, NSString *format, ...);
Hyperlog.m
#import "HyperLog.h"
void HyperLog(const char *file, int lineNumber, const char *functionName, NSString *format, ...)
{
va_list ap;
va_start (ap, format);
if (![format hasSuffix: @"\n"])
{
format = [format stringByAppendingString: @"\n"];
}
NSString *body = [[NSString alloc] initWithFormat:format arguments:ap];
va_end (ap);
NSString *fileName = [[NSString stringWithUTF8String:file] lastPathComponent];
char mesg[8192]="\0";
NSDate *now =[NSDate date];
NSString *dateString = [NSDateFormatter localizedStringFromDate:now dateStyle:NSDateFormatterShortStyle timeStyle:NSDateFormatterMediumStyle];
if ( sprintf( mesg, "<%s.%03.0f> : %s\n<%s : %d - %s>\n", [dateString UTF8String],roundf(fmod( [now timeIntervalSinceReferenceDate], 1 ) * 1000), [body UTF8String], [fileName UTF8String],
lineNumber,
functionName) < 0 ) printf("message creation failed\n");
fprintf(stderr, "%s", mesg );
}
然后,您只需要将这两行代码放在任何一个程序文件的顶部即可使其工作。
#define HYPER_LOG
#import "HyperLog.h"
我尝试使用Thomas的上述代码,使用C函数将系统生成的错误日志结果数据写入文本文件,在其他上下文中正常工作,但它一直崩溃,并且错误原因在过程中丢失。有没有人知道为什么?
do
循环是否有可能错误地测试了错误或终止条件,而不是缺少这些条件? - algal