The Open Group Base Specifications Issue 6
IEEE Std 1003.1, 2004 Edition
Copyright © 2001-2004 The IEEE and The Open Group, All Rights reserved.
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NAME

signbit - test sign

SYNOPSIS

#include <math.h>

int signbit(real-floating x);

DESCRIPTION

[CX] [Option Start] The functionality described on this reference page is aligned with the ISO C standard. Any conflict between the requirements described here and the ISO C standard is unintentional. This volume of IEEE Std 1003.1-2001 defers to the ISO C standard. [Option End]

The signbit() macro shall determine whether the sign of its argument value is negative. NaNs, zeros, and infinities have a sign bit.

RETURN VALUE

The signbit() macro shall return a non-zero value if and only if the sign of its argument value is negative.

ERRORS

No errors are defined.

The following sections are informative.

EXAMPLES

None.

APPLICATION USAGE

None.

RATIONALE

None.

FUTURE DIRECTIONS

None.

SEE ALSO

fpclassify(), isfinite(), isinf(), isnan(), isnormal(), the Base Definitions volume of IEEE Std 1003.1-2001, <math.h>

CHANGE HISTORY

First released in Issue 6. Derived from the ISO/IEC 9899:1999 standard.

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