Using gcc 4.3.2-7 on Intel Pentium 4 running Fedora Core 10 and -std=gnu99 of
/* DFP TR 24732 == WG14 / N1176, N1312 */ #define __STDC_WANT_DEC_FP__ /* Tell implementation that we want Decimal FP */ #include <stdio.h> /* printf() */ int main(void){ if( 0.0DF ){ printf("0.0DF should be zero\n"); } return 0; } gets: 0.0DF should be zero -- Summary: if( 0.0DF ) is considered true Product: gcc Version: 4.3.2 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: tydeman at tybor dot com GCC host triplet: 4.3.2 GCC target triplet: 4.3.2 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39035