diff options
Diffstat (limited to 'lib/util/pm_c_util.h')
| -rw-r--r-- | lib/util/pm_c_util.h | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/lib/util/pm_c_util.h b/lib/util/pm_c_util.h index 01a07657..a093adb6 100644 --- a/lib/util/pm_c_util.h +++ b/lib/util/pm_c_util.h @@ -20,6 +20,13 @@ #define ROUND(X) (((X) >= 0) ? (int)((X)+0.5) : (int)((X)-0.5)) #undef ROUNDU #define ROUNDU(X) ((unsigned int)((X)+0.5)) + /* Note that imprecision in floating point arithmetic can make an exact + half fractional part round down instead of up. What should be + 1000.5 might actually be 1000.49999999999. + + Use 'pnm_unnormalized_sample' instead of ROUNDU(samplen*maxval) to get + consistent rounding up when you are unnormalizing sample values. + */ /* ROUNDUP rounds up to a specified multiple. E.g. ROUNDUP(22, 8) == 24 */ @@ -53,9 +60,11 @@ #else /* The test for __STDC__ is paranoid. It is there just in case some nonstandard compiler defines __STDC_VERSION__ in an arbitrary manner. + + We know GCC 2.95.3 has stdbool; not sure about earlier GCC 2. */ - #if ( defined(__GNUC__) && (__GNUC__ >= 3) ) || \ - ( defined(__STDC__) && (__STDC__ ==1) && \ + #if ( defined(__GNUC__) && (__GNUC__ >= 2) ) || \ + ( defined(__STDC__) && (__STDC__ == 1) && \ defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) ) #include <stdbool.h> #else |