# fabs(3p) [posix man page]

FABS(3P) POSIX Programmer's Manual FABS(3P)PROLOG

This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the correspond- ing Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.NAME

fabs, fabsf, fabslabsolute value function--SYNOPSIS

#include <math.h> double fabs(double x); float fabsf(float x); long double fabsl(long double x);DESCRIPTION

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 POSIX.1-2008 defers to the ISO C standard. These functions shall compute the absolute value of their argument x,|x|.RETURN VALUE

Upon successful completion, these functions shall return the absolute value of x. If x is NaN, a NaN shall be returned. If x is +-0, +0 shall be returned. If x is +-Inf, +Inf shall be returned.ERRORS

No errors are defined. The following sections are informative.EXAMPLES

Computing the 1-Norm of a Floating-Point Vector This example shows the use of fabs() to compute the 1-norm of a vector defined as follows: norm1(v) = |v[0]| + |v[1]| + ... + |v[n-1]| where |x| denotes the absolute value of x, n denotes the vector's dimension v[i] denotes the i-th component of v (0<=i<n). #include <math.h> double norm1(const double v[], const int n) { int i; double n1_v; /* 1-norm of v */ n1_v = 0; for (i=0; i<n; i++) { n1_v += fabs (v[i]); } return n1_v; }APPLICATION USAGE

None.RATIONALE

None.FUTURE DIRECTIONS

None.SEE ALSO

isnan() The Base Definitions volume of POSIX.1-2008, <math.h>COPYRIGHT

Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2013 Edition, Standard for Information Technol- ogyPortable Operating System Interface (POSIX), The Open Group Base Specifications Issue 7, Copyright (C) 2013 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Stan- dard is the referee document. The original Standard can be obtained online at http://www.unix.org/online.html . Any typographical or formatting errors that appear in this page are most likely to have been introduced during the conversion of the source files to man page format. To report such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html .--IEEE

/The Open Group 2013 FABS(3P)

## Check Out this Related Man Page

FMIN(3P) POSIX Programmer's Manual FMIN(3P)PROLOG

This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the correspond- ing Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.NAME

fmin, fminf, fminldetermine minimum numeric value of two floating-point numbers--SYNOPSIS

#include <math.h> double fmin(double x, double y); float fminf(float x, float y); long double fminl(long double x, long double y);DESCRIPTION

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 POSIX.1-2008 defers to the ISO C standard. These functions shall determine the minimum numeric value of their arguments. NaN arguments shall be treated as missing data: if one argu- ment is a NaN and the other numeric, then these functions shall choose the numeric value.RETURN VALUE

Upon successful completion, these functions shall return the minimum numeric value of their arguments. If just one argument is a NaN, the other argument shall be returned. If x and y are NaN, a NaN shall be returned.ERRORS

No errors are defined. The following sections are informative.EXAMPLES

None.APPLICATION USAGE

None.RATIONALE

None.FUTURE DIRECTIONS

None.SEE ALSO

fdim(), fmax() The Base Definitions volume of POSIX.1-2008, <math.h>COPYRIGHT

Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2013 Edition, Standard for Information Technol- ogyPortable Operating System Interface (POSIX), The Open Group Base Specifications Issue 7, Copyright (C) 2013 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Stan- dard is the referee document. The original Standard can be obtained online at http://www.unix.org/online.html . Any typographical or formatting errors that appear in this page are most likely to have been introduced during the conversion of the source files to man page format. To report such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html .--IEEE

/The Open Group 2013 FMIN(3P)