timeval

Reinitialize timeval struct

由 半城伤御伤魂 提交于 2020-01-02 02:38:40
问题 How can I reinitialize a timeval struct from time.h? I recognize that I can reset both of the members of the struct to zero, but is there some other method I am overlooking? 回答1: The completely correct and portable (albeit C99) way to zero-initialize arbitrary (possibly aggregate) types: myTime = (struct timeval){0}; This works even for structures that contain pointers and floating point members, even if the implementation does not use all-zero-bits as the representations for null pointers

Strange errors using timeval struct and gettimeofday —because of semicolon in #define

由 一曲冷凌霜 提交于 2019-12-24 11:31:13
问题 I am getting a couple of weird compilation errors. This is for a homework assignment (help is ok). The idea is to implement a program that tests how well the user can hit "enter" once a second. I'm supposed to use gettimeofday to get some time values for each "enter" and then find out what the average time is and standard deviation... I'm trying to do this by checking stdin for '\n' and then if true, using gettimeofday to populate a timeval struct, then store said struct in an array for later

How to convert std::chrono::system_clock::duration into struct timeval

由 ◇◆丶佛笑我妖孽 提交于 2019-12-21 05:20:15
问题 The title says it all. I have to implement a function that receives a std::chrono::system_clock::duration value and that needs to convert it into a timeval sruct so I can pass it to some system function. 回答1: More general implementation. template<typename Duration> void to_timeval(Duration&& d, struct timeval & tv) { std::chrono::seconds const sec = std::chrono::duration_cast<std::chrono::seconds>(d); tv.tv_sec = sec.count(); tv.tv_usec = std::chrono::duration_cast<std::chrono::microseconds>

Switching between statements if the user inputs something: infinitely and with a timeout [duplicate]

由 那年仲夏 提交于 2019-12-11 14:13:28
问题 This question already has answers here : Is it necessary to reset the fd_set between select system call? (2 answers) Closed 4 years ago . To explain more clearly what I want to do, I want my code to check if the user inputs something (or if another file descriptor than 0 has data to read) every (let's say) 2.5 seconds and so until the program stops. If the user inputs something, a simple printf() will notify him and then the program will check again if the user inputs something in the next 2

how to calculate milliseconds using timeval structure?

由 旧城冷巷雨未停 提交于 2019-12-10 21:11:15
问题 I want to retrieve values in milliseconds from a variable of type timeval. Below is my attempt: timeval* time; long int millis = (time->tv_sec * 1000) + (time->tv_usec / 1000); printf("Seconds : %ld, Millis : %ld", time->tv_sec, millis); Output => Seconds : 1378441469, Millis : -243032358 Issue is I am getting millisecond values in minus. What is wrong with this snippets? 回答1: Assuming you did correctly initialize time , it's because you're overflowing when multiplying time->tv_sec by 1000.

Porting time APIs from Linux to Visual Studio 2008

由 你。 提交于 2019-12-06 05:17:54
问题 I have an application that I am porting to Microsoft Visual Studio 2008 that builds and runs fine on Linux. I am having trouble with the time routines, my Linux code looks like this: #include <sys/types.h> #include <sys/time.h> typedef long long Usec; inline Usec timevalToUsec(const timeval &tv) { return (((Usec) tv.tv_sec) * 1000000) + ((Usec) tv.tv_usec); } But the compiler fails on the sys/time.h header file: fatal error C1083: Cannot open include file: 'sys/time.h': No such file or

Is there a standard way to convert a struct timeval into a struct timespec?

由 我只是一个虾纸丫 提交于 2019-12-05 15:23:09
问题 struct timeval represents and instant in time with two members, tv_sec (seconds) and tv_usec (microseconds). In this representation, tv_usec is not by itself an absolute time it is a sub second offset off of tv_sec . struct timespec works the same way except that instead of microseconds it's offset ( tv_nsec ) is stored in nanosecond units. The question is: Is there a standard way to convert between these two? 回答1: Looking at this doc, I would think multiplying tv_usec by 1000 is sufficient

Reinitialize timeval struct

由 允我心安 提交于 2019-12-05 05:37:39
How can I reinitialize a timeval struct from time.h? I recognize that I can reset both of the members of the struct to zero, but is there some other method I am overlooking? The completely correct and portable (albeit C99) way to zero-initialize arbitrary (possibly aggregate) types: myTime = (struct timeval){0}; This works even for structures that contain pointers and floating point members, even if the implementation does not use all-zero-bits as the representations for null pointers and floating point zeros. memset may happen to work on your platform, but it is actually not the recommended

Porting time APIs from Linux to Visual Studio 2008

由 限于喜欢 提交于 2019-12-04 10:43:02
I have an application that I am porting to Microsoft Visual Studio 2008 that builds and runs fine on Linux. I am having trouble with the time routines, my Linux code looks like this: #include <sys/types.h> #include <sys/time.h> typedef long long Usec; inline Usec timevalToUsec(const timeval &tv) { return (((Usec) tv.tv_sec) * 1000000) + ((Usec) tv.tv_usec); } But the compiler fails on the sys/time.h header file: fatal error C1083: Cannot open include file: 'sys/time.h': No such file or directory If I change the include to just time.h I get a different error with timeval not being defined:

Is there a standard way to convert a struct timeval into a struct timespec?

由 ↘锁芯ラ 提交于 2019-12-04 01:34:47
struct timeval represents and instant in time with two members, tv_sec (seconds) and tv_usec (microseconds). In this representation, tv_usec is not by itself an absolute time it is a sub second offset off of tv_sec . struct timespec works the same way except that instead of microseconds it's offset ( tv_nsec ) is stored in nanosecond units. The question is: Is there a standard way to convert between these two? Looking at this doc , I would think multiplying tv_usec by 1000 is sufficient to get tv_nsec . More important, I suspect is the source of the different structures: they could be filled
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