C の localtime() の引数は混乱を招く。

time_t timeVal;

time(&timeVal);

time_t timeVal;
time_t *p_time;

p_time = &timeVal;

time(p_time);

time_t timeVal;

time(timeVal);

time_t *p_time;

time(p_time);

#include <stdlib.h>

#include <math.h>

#include <time.h>

#include <sys/time.h>



#define	_ISOC99_SOURCE



#define DAYS    (60 * 60 * 24)

#define NORM    (DAYS * 365)

#define LEAP    (DAYS * 366)

#define EPOC    1970



typedef unsigned int bool;



static const bool TRUE = 1;

static const bool FALSE= 0;



short ttl[13] = {0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365};

short mon[13] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};

enum date {Thu, Fri, Sat, Sun, Mon, Tue, Wed};



///////////////////////////////////////////////////////////////////

// localtime_s()

// 機能    : 年・月・日・曜日・時・分・秒・通算経過日数・夏時間を出力

//

// 入力    :

//     第一引数: *tm

//           型: tm 構造体へのポインター   

//     第二引数: t

//           型: unsigned long

//

// 出力    :     *tm 

//           型: tm 構造体へのポインター

//

// 戻り値  : 論理型

//           TRUE : 1

//           FALSE: 0

//

///////////////////////////////////////////////////////////////////

bool localtime_s(struct tm *tm, time_t t)

{

    enum date wday = Thu;

    time_t now;

    unsigned long tmp = 0L, temp=0L, leap=0L;

    unsigned int y, m, month, h, mn, s, c, zg, rem, cur;

    double d, days, gap;

    short i=0;

    char *TZ, tz[4];

    char flg = '0';



    /* 初期化 */

    y = m = month = h = mn = s = c = zg = rem = cur = 0;

    d = days = 0.0000;



    /* 1970年1月1日から指定年度まで */

    for(tmp = 0; tmp <= t; tmp += NORM){

        if(tmp + NORM >= t){

            tmp -= NORM;

            break;

        }



        c = y + EPOC;



        if(!(c % 4) && ((c % 100) || !(c % 400))){

            leap++;

        }



        y++;

    }



    leap *= DAYS;

    gap = (double)t - (tmp + leap);



    temp = Sun;

    temp += t / DAYS;

    if(!(c % 4) && ((c % 100) || !(c % 400))) temp++;

    temp %= 7;



    if(gap > 0.000) days = gap / DAYS;

    else days = 1;



    for(i = 1; i <= 12; i++){

        if(gap > (ttl[1] * DAYS)){

            if(gap <= (ttl[i + 1] * DAYS)){

                month = i + 1;

                d = (double)(gap / DAYS) - ttl[i];



                if(d >= 0.000 && d < 1.000) d = 1.000;

                else d++;



                temp++;



                break;

            }

        }

        else {

            if(gap > 0.000){

                d = (double)(gap / DAYS);

                d++;

            }

            else d = 1.000;

            temp++;



            month = i;



            break;

        }

    } 



    /* 指定時刻時・分・秒の割出し */

    h  = t % DAYS;

    mn = h % (60 * 60);

    s  = mn % 60;



    h  /= (60 * 60);

    mn /= 60;



    /* タイムゾーン増減 */

    TZ = (char *)getenv("TZ");

    memset(tz, 0x00, sizeof(tz));

    strncpy(tz, (TZ + 3), 3);



    /* atoi() */

    for(i=1, zg=0; i <= strlen(&tz[1]); i++){

        zg *= 10;

        zg += (tz[i] - 0x30);

    }



    if(h + zg >= 24){

        if(month == 12 && d == (double)mon[month]){

            c++;



            month = 1;

            wday = 1;

            d = 1.000;

            days = 1.000;

        }

        else {

            d = d + 1.000;

            // 月末調整

            if(d > mon[month] + 1){

                month++;

                d = 1.000;

            }



            days++;

        }



        temp++;

    }



/*

    time(&now);

    cur = now / NORM;

    cur += 1970;



    /* ローカライズタイム

    if(cur == y)

*/

    h += zg;



    if(h >= 24){

        h %= 24;

    }



    wday = temp;

    if(wday > 6){

        wday %= 7;

    }



    /* 第一引数構造体へ代入 */

    tm->tm_sec = s;

    tm->tm_min = mn;

    tm->tm_hour = h;

    tm->tm_mday = (int)d;

    tm->tm_mon = month;

    tm->tm_year = c;

    tm->tm_wday = wday;

    tm->tm_yday = (int)days;

    tm->tm_isdst = 0;



    /* 成功 */

    return(TRUE);

}



int main()

{

    time_t t;

    struct tm tm;

    static unsigned char *date[] = {"日", "月", "火", "水", "木", "金", "土" };

    unsigned char buf[7];

    char *Z;



    time(&t);



    localtime_s(&tm, t);



    Z = (char *)getenv("TZ");



    memset(buf, 0x00, sizeof(buf));

    strncpy(buf, Z, 3);



    printf("%d年", tm.tm_year);

    printf("%02d月", tm.tm_mon);

    printf("%02d日 ", tm.tm_mday);

    printf("(%s) ", date[tm.tm_wday]);

    printf("%02d時", tm.tm_hour);

    printf("%02d分", tm.tm_min);

    printf("%02d秒", tm.tm_sec);

    printf(" %d日目 ", tm.tm_yday);



    printf("%d ", tm.tm_isdst);

    printf("%s\n", buf);



    return(0);

}