objective-c gettimeofday function alternatives

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I'm using gettimeofday in my program for time intervals like that:

struct timeval currentTime, startTime; 
gettimeofday(&startTime, NULL);
startTime.tv_usec /= 1000;
gettimeofday(&currentTime, NULL);
currentTime.tv_usec /= 1000;

long int msSinceStart = (currentTime.tv_usec + (1000 * currentTime.tv_sec) ) - (startTime.tv_usec + (1000 * startTime.tv_sec) );

Is there any alternative for this?

@user2282782 Noted in their comments that the real issue behind the question was that the warning gettimeofday is invalid in c99 is being thrown in at compile time.

To resolve the issue, as @Emmanuel pointed out, just add: #include <sys/time.h> to the top of the file. That solved my same problem with this as well.

What's the best alternative library to gettimeofday() in C++?, There is no object-oriented interface for dealing with time and intervals that's part of the standard C++ library. You might want to look at Boost. Objective-C is defined as a small but powerful set of extensions to the standard ANSI C language. Its additions to C are mostly based on Smalltalk, one of the first object-oriented programming languages. Objective-C is designed to give C full object-oriented programming capabilities, and to do so in a simple and straightforward way.

The Objective-C alternative is NSDate.

NSDate *startTime = [NSDate date];
NSTimeInterval secondsSinceStart = -[startTime timeIntervalSinceNow];

Of course, if you want a hi-res time, you should be using mach_absolute_time (see https://developer.apple.com/library/mac/qa/qa1398/_index.html).

Computer Vision -- ACCV 2010 Workshops: ACCV 2010 International , @user2282782 Noted in their comments that the real issue behind the question was that the warning gettimeofday is invalid in c99 is being thrown in at compile  The functions gettimeofday() and settimeofday() can get and set the time as well as a timezone. The tv argument is a struct timeval (as specified in <sys/time.h>): struct timeval { time_t tv_sec; /* seconds */ suseconds_t tv_usec; /* microseconds */ };

You can also use CFAbsoluteTimeGetCurrent:

CFAbsoluteTime start = CFAbsoluteTimeGetCurrent();

and to get the number of seconds that have elapsed:

CFTimeInterval elapsed = CFAbsoluteTimeGetCurrent() - start;

Note, the documentation for CFAbsoluteTimeGetCurrent warns us:

Repeated calls to this function do not guarantee monotonically increasing results. The system time may decrease due to synchronization with external time references or due to an explicit user change of the clock.

This means that if you're unfortunate enough to measure elapsed time when one of these adjustments take place, you can end up with incorrect elapsed time calculation. This caveat also applies to NSDate and similar functions. To get around this, you can use CACurrentMediaTime:

CFTimeInterval start = CACurrentMediaTime();


CFTimeInterval elapsed = CACurrentMediaTime() - start;

This uses mach_absolute_time, but avoids some of its complexities outlined in Technical Q&A QA1398.

gettimeofday(2) - Linux manual page, We evaluated the performance of the proposed elimination method through of the walking person in Fig. 5(c)). However, the proposed method outperformed the We also confirmed that the proposed method is a potential alternative to the to recover the incorrectly eliminated motion vectors of moving object regions. what is alternative function in Objective C as like php rand() function ? Hi i know the PHP very well but learning the Objective C in ios and want to know if function related to generate random no as we do in php with rand() echo rand();//it will print random number with each run it generate unique no.

Now to resolve this issue you should insert to your file this:

#import <UIKit/UIKit.h>

Monotonicity of gettimeofday() [LWN.net], #include <sys/time.h> int gettimeofday(struct timeval *tv, struct timezone *tz); int The functions gettimeofday() and settimeofday() can get and set the time as well as a C library/kernel differences On some architectures, an implementation of  This was on an Intel Pentium 4 (i386) running Windows XP and using Visual Studio 2005. Where should gettimeofday be defined? I would rather use one of those nice asm versions of hardclock, but MSVC use __asm not asm() and the syntax of the asm is intel vs AT&T, as such I have turned off the HAVEASM option in config.h

The CACurrentMediaTime() function exists in Cocos2dx?, The time is always a mono- tonically increasing function. I looked in kernel/time​.c for Linux 2.4.20, and it mentions that Linux's time-keeping paradigm is based on NTP-style updates I looked in that paper, and it indicated that monotonicity is a goal of that algorithm. The alternative is not that expensive. objective-c gettimeofday function alternatives. 2014-03-20 objective-c gettimeofday. In what cases CLOCK_MONOTONIC might not be available. 2018-07-15

gettimeofday missing in timing.c - Discussion Forum, Anyone know another alternative for this function? I've seen some tutorials on Objective-C. They use CACurrentMediaTime function to build the examples. void Director::calculateDeltaTime() { struct timeval now; if (gettimeofday(&now,  I want to take current time with milli seconds in C. Does it have any header file to include to produce time in milli seconds. Please mail me if any of u know. You may try the "gettimeofday" function. It reports the time down to microsecond level. The function is included via <sys/time.h>.

API Design for C++, When compiling timing.c on win32 I get Error 4 error LNK2019: external symbol _gettimeofday referenced in function _hardclock timing.obj The strptime() function is the converse of strftime(3); it converts the character string pointed to by s to values which are stored in the "broken-down time" structure pointed to by tm, using the format specified by format.

  • gettimeofday deprecated with Xcode 5.1 ?? where this came from ?
  • it shows a warning "implicit declaration of function 'gettimeofday' is invalid in c99"
  • Implicit declaration of a function, doesn't mean deprecated… Just include <sys/time.h> and the error vanished.
  • @user2282782 your question should be demanding solution, if there is no option then should go for alternative, emmanuel is right