https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92076
Bug ID: 92076
Summary: strange strcpy
Product: gcc
Version: 6.3.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: georg.chambert at telia dot com
Target Milestone: ---
Created attachment 47026
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=47026&action=edit
screenshot of strange strcpy buffer shift, note first two printf
-----------------------snippet of code ---------------------v
printf("%s\n",prev_buff);
strcpy(str,prev_buff); str[2]=0;// take first part an put
endmark
lastHour = atoi(str);
printf("%s\n",prev_buff);
str[0]=prev_buff[3]; str[1]=prev_buff[4];str[2]=0;// hittar
inget bra i clib
lastMin = atoi(str);
printf(">>>%d<<<%s>>>%d<<<\n",lastHour,str,lastMin);
printf("%s\n",prev_buff);
------------------------
the bugg (well strangeity then) occur (as per screenshot) between the first and
the second printf,
the prev_buff gets "shifted left", 10positions, BY the strcpy( ) CALL(!!??) ;
in my naive world the prev_buff should be unaltered.
exactly the same sequence of code works without problem in an earlier location,
albeit with other
variables (and without the issue-confining/indicating printouts)
(which is worrying);
---------------------------------just preceeding
strcpy(str,inbuffer); str[2]=0;// take first part an put
endmark
firstHour = atoi(str);
str[0]=inbuffer[3]; str[1]=inbuffer[4];str[2]=0;// hittar
inget bra i clib
firstMin = atoi(str);
printf(">>>%d<<<>>>%d<<<\n",firstHour,firstMin);
---------------------declaration earlier in program-----------------------v
#define WIN32_LEAN_AND_MEAN
#include <stdio.h>
#include <stdlib.h>
#include <windows.h>
using namespace std;
....
char inbuffer[80];
char prev_buff[80];
char str[10];
----------------------------------------------------------------------------
---- has been compiled with following, making no diff -----------v
C:\Users\Micron 2.0.DESKTOP-OKJ8P06\Desktop\logg_read>gcc -fno-strict-aliasing
-fwrapv -fno-aggressive-loop-optimizations measProc.cpp
------------------------------------------------------------------
AS for the GCC version used:
C:\Users\Micron 2.0.DESKTOP-OKJ8P06>gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=c:/mingw/bin/../libexec/gcc/mingw32/6.3.0/lto-wrapper.exe
Target: mingw32
Configured with: ../src/gcc-6.3.0/configure --build=x86_64-pc-linux-gnu
--host=mingw32 --target=mingw32 --with-gmp=/mingw --with-mpfr --with-mpc=/mingw
--with-isl=/mingw --prefix=/mingw --disable-win32-registry --with-arch=i586
--with-tune=generic --enable-languages=c,c++,objc,obj-c++,fortran,ada
--with-pkgversion='MinGW.org GCC-6.3.0-1' --enable-static --enable-shared
--enable-threads --with-dwarf2 --disable-sjlj-exceptions
--enable-version-specific-runtime-libs --with-libiconv-prefix=/mingw
--with-libintl-prefix=/mingw --enable-libstdcxx-debug --enable-libgomp
--disable-libvtv --enable-nls
Thread model: win32
gcc version 6.3.0 (MinGW.org GCC-6.3.0-1)
THE machine is a laptop ASUS (in search of increadable; which they will never
find) with Windows 10 (worst OS ever)
