keil中的<time.h>有没有对应的库函数

bigbat

keil中的<time.h>有没有对应的库函数 [复制链接]

我在项目中引用了<time.h>声明，似乎keil并没有实现相应的功能，只是给出了一个空声明。对应的函数好象需要自己实现，就如同pritf函数一样。

求各位高手指点！谢谢。

#pragma pop

   /* struct tm holds the components of a calendar time, called the broken-down
    * time. The value of tm_isdst is positive if Daylight Savings Time is in
    * effect, zero if Daylight Savings Time is not in effect, and negative if
    * the information is not available.
    */

extern _ARMABI clock_t clock(void);
   /* determines the processor time used.
    * Returns: the implementation's best approximation to the processor time
    *          used by the program since program invocation. The time in
    *          seconds is the value returned divided by the value of the macro
    *          CLK_TCK. The value (clock_t)-1 is returned if the processor time
    *          used is not available.
    */
extern _ARMABI double difftime(time_t /*time1*/, time_t /*time0*/);
   /*
    * computes the difference between two calendar times: time1 - time0.
    * Returns: the difference expressed in seconds as a double.
    */
extern _ARMABI time_t mktime(struct tm * /*timeptr*/) __attribute__((__nonnull__(1)));
   /*
    * converts the broken-down time, expressed as local time, in the structure
    * pointed to by timeptr into a calendar time value with the same encoding
    * as that of the values returned by the time function. The original values
    * of the tm_wday and tm_yday components of the structure are ignored, and
    * the original values of the other components are not restricted to the
    * ranges indicated above. On successful completion, the values of the
    * tm_wday and tm_yday structure components are set appropriately, and the
    * other components are set to represent the specified calendar time, but
    * with their values forced to the ranges indicated above; the final value
    * of tm_mday is not set until tm_mon and tm_year are determined.
    * Returns: the specified calendar time encoded as a value of type time_t.
    *          If the calendar time cannot be represented, the function returns
    *          the value (time_t)-1.
    */
extern _ARMABI time_t time(time_t * /*timer*/);
   /*
    * determines the current calendar time. The encoding of the value is
    * unspecified.
    * Returns: the implementations best approximation to the current calendar
    *          time. The value (time_t)-1 is returned if the calendar time is
    *          not available. If timer is not a null pointer, the return value
    *          is also assigned to the object it points to.
    */

extern _ARMABI char *asctime(const struct tm * /*timeptr*/) __attribute__((__nonnull__(1)));
extern _ARMABI char *_asctime_r(const struct tm * /*timeptr*/,
                                char * __restrict /*buf*/) __attribute__((__nonnull__(1,2)));
#ifndef __STRICT_ANSI__
extern _ARMABI char *asctime_r(const struct tm * /*timeptr*/,
                               char * __restrict /*buf*/) __attribute__((__nonnull__(1,2)));
#endif

 

hotsauce1861

具体的函数实现应该在lib里了，所以你直接用头文件里的接口就好了阿