怎样获取毫秒级时间（C/C++）
目的：获取毫秒级别时间，要求精确度高，稳定性好 VC++2010 C/C++?
[解决办法]
usleep();
select();
//可精确至百万分之一秒
[解决办法]
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#ifdef WIN32
#include <windows.h>
#include <io.h>
#else
#include <unistd.h>
#include <sys/time.h>
#include <pthread.h>
#define CRITICAL_SECTION pthread_mutex_t
#define _vsnprintf vsnprintf
#endif
//Log{
#define MAXLOGSIZE 20000000
#define MAXLINSIZE 16000
#include <time.h>
#include <sys/timeb.h>
#include <stdarg.h>
char logfilename1[]="MyLog1.log";
char logfilename2[]="MyLog2.log";
static char logstr[MAXLINSIZE+1];
char datestr[16];
char timestr[16];
char mss[4];
CRITICAL_SECTION cs_log;
FILE *flog;
#ifdef WIN32
void Lock(CRITICAL_SECTION *l) {
EnterCriticalSection(l);
}
void Unlock(CRITICAL_SECTION *l) {
LeaveCriticalSection(l);
}
#else
void Lock(CRITICAL_SECTION *l) {
pthread_mutex_lock(l);
}
void Unlock(CRITICAL_SECTION *l) {
pthread_mutex_unlock(l);
}
#endif
void LogV(const char *pszFmt,va_list argp) {
struct tm *now;
struct timeb tb;
if (NULL==pszFmt
[解决办法]
0==pszFmt[0]) return;
_vsnprintf(logstr,MAXLINSIZE,pszFmt,argp);
ftime(&tb);
now=localtime(&tb.time);
sprintf(datestr,"%04d-%02d-%02d",now->tm_year+1900,now->tm_mon+1,now->tm_mday);
sprintf(timestr,"%02d:%02d:%02d",now->tm_hour ,now->tm_min ,now->tm_sec );
sprintf(mss,"%03d",tb.millitm);
printf("%s %s.%s %s",datestr,timestr,mss,logstr);
flog=fopen(logfilename1,"a");
if (NULL!=flog) {
fprintf(flog,"%s %s.%s %s",datestr,timestr,mss,logstr);
if (ftell(flog)>MAXLOGSIZE) {
fclose(flog);
if (rename(logfilename1,logfilename2)) {
remove(logfilename2);
rename(logfilename1,logfilename2);
}
} else {
fclose(flog);
}
}
}
void Log(const char *pszFmt,...) {
va_list argp;
Lock(&cs_log);
va_start(argp,pszFmt);
LogV(pszFmt,argp);
va_end(argp);
Unlock(&cs_log);
}
//Log}
int main(int argc,char * argv[]) {
int i;
#ifdef WIN32
InitializeCriticalSection(&cs_log);
#else
pthread_mutex_init(&cs_log,NULL);
#endif
for (i=0;i<10000;i++) {
Log("This is a Log %04d from FILE:%s LINE:%d\n",i, __FILE__, __LINE__);
}
#ifdef WIN32
DeleteCriticalSection(&cs_log);
#else
pthread_mutex_destroy(&cs_log);
#endif
return 0;
}
//1-78行添加到你带main的.c或.cpp的那个文件的最前面
//81-85行添加到你的main函数开头
//89-93行添加到你的main函数结束前
//在要写LOG的地方仿照第87行的写法写LOG到文件MyLog1.log中
[解决办法]
x86可以用rdtsc指令取，取完除一下CPU的主频就是整秒，拿它来算，没有比这个更敏感的了。连着取两次也保证能计算出时间差来。不过这个只适合取时间差。
------解决方案--------------------
这是15ms级别的，不是1ms级别的
[解决办法]
_ftime
Gets the current time.
void _ftime( struct _timeb *timeptr );
Function Required Header Compatibility
_ftime <sys/types.h> and <sys/timeb.h> Win 95, Win NT
For additional compatibility information, see Compatibility in the Introduction.
Libraries
LIBC.LIB Single thread static library, retail version
LIBCMT.LIB Multithread static library, retail version
MSVCRT.LIB Import library for MSVCRT.DLL, retail version
Return Value
_ftime does not return a value, but fills in the fields of the structure pointed to by timeptr.
Parameter
timeptr
Pointer to _timeb structure
Remarks
The _ftime function gets the current local time and stores it in the structure pointed to by timeptr. The _timeb structure is defined in SYS\TIMEB.H. It contains four fields:
dstflag
Nonzero if daylight savings time is currently in effect for the local time zone. (See _tzset for an explanation of how daylight savings time is determined.)
millitm
Fraction of a second in milliseconds.
time
Time in seconds since midnight (00:00:00), January 1, 1970, coordinated universal time (UTC).
timezone
Difference in minutes, moving westward, between UTC and local time. The value of timezone is set from the value of the global variable _timezone (see _tzset).
Example
/* FTIME.C: This program uses _ftime to obtain the current
* time and then stores this time in timebuffer.
*/
#include <stdio.h>
#include <sys/timeb.h>
#include <time.h>
void main( void )
{
struct _timeb timebuffer;
char *timeline;
_ftime( &timebuffer );
timeline = ctime( & ( timebuffer.time ) );
printf( "The time is %.19s.%hu %s", timeline, timebuffer.millitm, &timeline[20] );
}
Output
The time is Tue Mar 21 15:26:41.341 1995
Time Management Routines
See Also asctime, ctime, gmtime, localtime, time