fpclassify, isfinite, isnormal, isnan, isinf - floating-point classification macros
#include <math.h> int fpclassify(x); int isfinite(x); int isnormal(x); int isnan(x); int isinf(x); Link with -lm. Feature Test Macro Requirements for glibc (see feature_test_macros(7)): fpclassify(), isfinite(), isnormal(): _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L isnan(): _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE || /* Since glibc 2.19: */ _DEFAULT_SOURCE || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE isinf(): _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L || /* Since glibc 2.19: */ _DEFAULT_SOURCE || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
Floating point numbers can have special values, such as infinite or NaN. With the macro fpclassify(x) you can find out what type x is. The macro takes any floating-point expression as argument. The result is one of the following values: FP_NAN x is "Not a Number". FP_INFINITE x is either positive infinity or negative infinity. FP_ZERO x is zero. FP_SUBNORMAL x is too small to be represented in normalized format. FP_NORMAL if nothing of the above is correct then it must be a normal floating-point number. The other macros provide a short answer to some standard questions. isfinite(x) returns a nonzero value if (fpclassify(x) != FP_NAN && fpclassify(x) != FP_INFINITE) isnormal(x) returns a nonzero value if (fpclassify(x) == FP_NORMAL) isnan(x) returns a nonzero value if (fpclassify(x) == FP_NAN) isinf(x) returns 1 if x is positive infinity, and -1 if x is negative infinity.
For an explanation of the terms used in this section, see attributes(7). Interface Attribute Value fpclassify(), isfinite(), Thread safety MT-Safe isnormal(), isnan(), isinf()
POSIX.1-2001, POSIX.1-2008, C99. For isinf(), the standards merely say that the return value is nonzero if and only if the argument has an infinite value.
In glibc 2.01 and earlier, isinf() returns a nonzero value (actually: 1) if x is positive infinity or negative infinity. (This is all that C99 requires.)
This page is part of release 4.09 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at https://www.kernel.org/doc/man-pages/. 2016-03-15 FPCLASSIFY(3)
More Linux Commands
vhangup(8) - Cause a virtually hangup on the specified termi
vhangup simulates a hangup on the specified terminals. Not existing device files or devices will be ignored. EXAMPLES vhangup /dev/tty1 /dev/tty2 /dev/tty3 /dev
git-stage(1) - Add file contents to the staging area........
This is a synonym for git-add(1). Please refer to the documentation of that command. GIT Part of the git(1) suite git-stage.1 (Commands - Linux manual page)
Tk_GetAtomName(3) - manage cache of X atoms - Linux man page
These procedures are similar to the Xlib procedures XInternAtom and XGetAtomName. Tk_InternAtom returns the atom identifier associated with string given by name
gobject-query(1) - display a tree of types - Linux man page
gobject-query is a small utility that draws a tree of types. gobject-query takes a mandatory argument that specifies whether it should iterate over the fundamen
XEqualRegion(3) - determine if regions are empty or equal...
The XEmptyRegion function returns True if the region is empty. The XEqualRegion function returns True if the two regions have the same offset, size, and shape.
more(1) - file perusal filter for crt viewing (Man Page)....
more is a filter for paging through text one screenful at a time. This version is especially primitive. Users should realize that less(1) provides more(1) emula
audit_get_reply(3) - Get the audit system's reply (ManPage)
This function gets the next data packet sent on the audit netlink socket. This function is usually called after sending a command to the audit system. fd should
getpid(2) - get process identification - Linux manual page
getpid() returns the process ID of the calling process. (This is often used by routines that generate unique temporary filenames.) getppid() returns the process
SDL_SetPalette(3) - Sets the colors in the palette of an 8-b
Sets a portion of the palette for the given 8-bit surface. Palettized (8-bit) screen surfaces with the SDL_HWPALETTE flag have two palettes, a logical palette t
vcsa(4) - virtual console memory (Special - Linux man page)
/dev/vcs0 is a character device with major number 7 and minor number 0, usually of mode 0644 and owner root.tty. It refers to the memory of the currently displa
nice(2) - change process priority - Linux manual page.......
nice() adds inc to the nice value for the calling process. (A higher nice value means a low priority.) Only the superuser may specify a negative increment, or p
Mail::SPF::Result(3pm) - SPF result class - Linux man page
An object of class Mail::SPF::Result represents the result of an SPF request. There is usually no need to construct an SPF result object directly using the new