FDIM(3)                                                                 Linux Programmer's Manual                                                                FDIM(3)

NAME
       fdim, fdimf, fdiml - positive difference

SYNOPSIS
       #include <math.h>

       double fdim(double x, double y);
       float fdimf(float x, float y);
       long double fdiml(long double x, long double y);

       Link with -lm.

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       fdimf(), fdiml():
           _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L

DESCRIPTION
       These functions return the positive difference, max(x-y,0), between their arguments.

RETURN VALUE
       On success, these functions return the positive difference.

       If x or y is a NaN, a NaN is returned.

       If the result overflows, a range error occurs, and the functions return HUGE_VAL, HUGE_VALF, or HUGE_VALL, respectively.

ERRORS
       See math_error(7) for information on how to determine whether an error has occurred when calling these functions.

       The following errors can occur:

       Range error: result overflow
              errno is set to ERANGE.  An overflow floating-point exception (FE_OVERFLOW) is raised.

VERSIONS
       These functions first appeared in glibc in version 2.1.

ATTRIBUTES
       For an explanation of the terms used in this section, see attributes(7).

       ┌──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┬───────────────┬─────────┐
       │Interface                                                                                                                             │ Attribute     │ Value   │
       ├──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┼───────────────┼─────────┤
       │fdim(), fdimf(), fdiml()                                                                                                              │ Thread safety │ MT-Safe │
       └──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┴───────────────┴─────────┘

CONFORMING TO
       C99, POSIX.1-2001, POSIX.1-2008.

BUGS
       Before glibc version 2.24 on certain architectures (e.g., x86, but not x86_64) these functions did not set errno.

SEE ALSO
       fmax(3)

                                                                               2021-03-22                                                                        FDIM(3)