From:	"Markus F.X.J. Oberhumer" <mfx AT Oeh DOT Uni-Linz DOT ac DOT at>
Message-Id:	<199610181233.NAA32624@osiris.oeh.uni-linz.ac.at>
Subject:	mktime() bug ?
To:	djgpp-workers AT delorie DOT com (djgpp-workers)
Date:	Fri, 18 Oct 1996 13:33:30 +0100 (MET)
Return-read-to:	mfx AT oeh DOT uni-linz DOT ac DOT at

===============================================================================
Markus F.X.J. Oberhumer <markus DOT oberhumer AT jk DOT uni-linz DOT ac DOT at>

Subject: mktime() bug ?
To: djgpp-workers AT delorie DOT com
===============================================================================

Some time ago I found a really annoying bug in mktime(). I encountered
it in stat() where it caused 'make' think that a file doesn't exist.

The bug prevented me to rebuild libc.a because out of the hundreds
of files in src/libc about 10 files had a timestamp that made mktime() fail.

Could someone please check if the following program works fine
with the latest snapshot ?


/***********************************************************************
// mktime fails on rare occasions
************************************************************************/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

int main(int argc, char *argv[])
{
    struct tm tmm;
    time_t t;
    const char *tz;

    /* the April 1995 bug can be reproduced with (at least) these timezones: */
    putenv("TZ=MET-1MEST");
    // putenv("TZ=e:/l/djgpp2/zoneinfo/met");
    // putenv("TZ=e:/l/djgpp2/zoneinfo/gmt-1");

    tzset();

    memset(&tmm, 0, sizeof(struct tm));
    tmm.tm_isdst = -1;    /* let mktime() determine if DST is in effect */
    tmm.tm_sec  = 40;
    tmm.tm_min  = 22;
    tmm.tm_hour = 2;
    tmm.tm_mday = 2;
    tmm.tm_year = 1995 - 1900;

    /* 0 = January */
    tmm.tm_mon  = 5 - 1;    /* May - this works with all timezones */
    tmm.tm_mon  = 4 - 1;    /* April - !!! this fails !!! */

    t = mktime(&tmm);
    if (t == (time_t) -1)
        printf("error !\n");
    else
        printf("%s",ctime(&t));
    
    tz = getenv("TZ");
    printf("TZ=%s\n", tz == NULL ? "" : tz);

    return 0;
}

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