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Re: Cast from double to int64_t/uint64_t : +/- inf handling ?

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On Wed, 25 Apr 2012 14:17:23 UTC, Xavier Roche <xroche@free.fr.NOSPAM.invalid> wrote:

> Are there any rules regarding cast result from double to 
> int64_t/uint64_t for positive/negative infinity, or is the result 
> totally undefined ?

If Annex F is being followed, the requirements are:

F.4 Floating to integer conversion

If the integer type is _Bool, 6.3.1.2 applies and no floating-point
exceptions are raised (even for NaN). Otherwise, if the floating value
is infinite or NaN or if the integral part of the floating value
exceeds the range of the integer type, then the ''invalid'' floating-
point exception is raised and the resulting value is
unspecified. Otherwise, the resulting value is determined by
6.3.1.4. Conversion of an integral floating value that does not exceed
the range of the integer type raises no floating-point exceptions;
whether conversion of a non-integral floating value raises the
''inexact'' floating-point exception is unspecified.360)

The public test case:
  http://www.tybor.com/tflt2int.c
shows how bad compilers do for that kind of conversion.
---
Fred J. Tydeman        Tydeman Consulting
tydeman@tybor.com      Testing, numerics, programming
+1 (775) 358-9748      Vice-chair of PL22.11 (ANSI "C")
Sample C99+FPCE tests: http://www.tybor.com
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Cast from double to int64_t/uint64_t : +/- inf handling ? Xavier Roche <xroche@free.fr.NOSPAM.invalid> - 2012-04-25 16:17 +0200
  Re: Cast from double to int64_t/uint64_t : +/- inf handling ? James Kuyper <jameskuyper@verizon.net> - 2012-04-25 11:37 -0400
    Re: Cast from double to int64_t/uint64_t : +/- inf handling ? Xavier Roche <xroche@free.fr.NOSPAM.invalid> - 2012-04-26 10:54 +0200
    Re: Cast from double to int64_t/uint64_t : +/- inf handling ? "christian.bau" <christian.bau@cbau.wanadoo.co.uk> - 2012-04-26 06:09 -0700
    Re: Cast from double to int64_t/uint64_t : +/- inf handling ? Tim Rentsch <txr@alumni.caltech.edu> - 2012-05-07 16:46 -0700
  Re: Cast from double to int64_t/uint64_t : +/- inf handling ? "Fred J. Tydeman" <tydeman.consulting@sbcglobal.net> - 2012-04-26 14:49 +0000

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