Pedro Izecksohn <[EMAIL PROTECTED]> wrote: > --- peternilsson42 wrote: > > "-Wconversion Warn for implicit conversions that may alter > > a value. ... " > > > > Integral promotions don't alter the value. > > > > Maybe you need -Wsign-conversion > > gcc -Wall -Wsign-conversion problem.c -o problem > cc1: error: unrecognized command line option "-Wsign-conversion"
Time you updated then... <http://gcc.gnu.org/onlinedocs/gcc-4.3.2/gcc/Option-Index.html#Option- Index> % gcc --version gcc.exe (GCC) 4.3.2 Copyright (C) 2008 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. % type problem.c #include <stdio.h> int main (void) { unsigned short int a; unsigned long long int b, c; a = -1; b = (a*a); c = ((unsigned int)a*(unsigned int)a); printf ("Why %llx != %llx ?\n", b, c); return 0; } % gcc -std=c99 -Wsign-conversion problem.c -o problem.exe problem.c: In function 'main': problem.c:6: warning: negative integer implicitly converted to unsigned type problem.c:7: warning: conversion to 'long long unsigned int' from 'int' may change the sign of the result % problem Why fffffffffffe0001 != fffe0001 ? -- Peter
