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Diffstat (limited to 'man3/signbit.3')
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diff --git a/man3/signbit.3 b/man3/signbit.3 new file mode 100644 index 000000000..428dd4eaa --- /dev/null +++ b/man3/signbit.3 @@ -0,0 +1,25 @@ +.\" Copyright 2002 Walter Harms (walter.harms@informatik.uni-oldenburg.de) +.\" Distributed under GPL +.\" Based on glibc infopages +.TH SIGNBIT 3 2002-08-10 "GNU" "libc math functions" +.SH NAME +signbit \- test sign of a real floating point number +.SH SYNOPSIS +.B "#include <math.h>" +.sp +.BI "int signbit (" X ");" +.sp +Link with \-lm. +.SH DESCRIPTION +`signbit' is a generic macro which can work on all real floating-point +types. It returns a nonzero value if the value of X has its sign +bit set. +.PP +This is not the same as `x < 0.0', because IEEE 754 floating point +allows zero to be signed. The comparison `-0.0 < 0.0' is false, +but `signbit (-0.0)' will return a nonzero value. +.SH "CONFORMING TO" +This function is defined in IEC 559 (and the appendix with +recommended functions in IEEE 754/IEEE 854). +.SH "SEE ALSO" +.BR copysign (3) |