fabs(3) Library Functions Manual fabs(3)
NAME
fabs, fabsf, fabsl - absolute value of floating-point number
LIBRARY
Math library (libm, -lm)
SYNOPSIS
#include <math.h>
double fabs(double x);
float fabsf(float x);
long double fabsl(long double x);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
fabsf(), fabsl():
_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
|| /* Since glibc 2.19: */ _DEFAULT_SOURCE
|| /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
DESCRIPTION
These functions return the absolute value of the floating-point number
x.
RETURN VALUE
These functions return the absolute value of x.
If x is a NaN, a NaN is returned.
If x is -0, +0 is returned.
If x is negative infinity or positive infinity, positive infinity is re-
turned.
ERRORS
No errors occur.
ATTRIBUTES
For an explanation of the terms used in this section, see attributes(7).
┌────────────────────────────────────────────┬───────────────┬─────────┐
│ Interface │ Attribute │ Value │
├────────────────────────────────────────────┼───────────────┼─────────┤
│ fabs(), fabsf(), fabsl() │ Thread safety │ MT-Safe │
└────────────────────────────────────────────┴───────────────┴─────────┘
STANDARDS
C11, POSIX.1-2008.
HISTORY
C99, POSIX.1-2001.
The variant returning double also conforms to SVr4, 4.3BSD, C89.
SEE ALSO
abs(3), cabs(3), ceil(3), floor(3), labs(3), rint(3)
Linux man-pages 6.9.1 2024-05-02 fabs(3)
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