Command:

ERFC(3) Linux Programmer's Manual ERFC(3)NAMEerfc, erfcf, erfcl - complementary error functionSYNOPSIS#include<math.h>doubleerfc(doublex);floaterfcf(floatx);longdoubleerfcl(longdoublex);Link with-lm. Feature Test Macro Requirements for glibc (see feature_test_macros(7)):erfc(): _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE || _ISOC99_SOURCE; orcc-std=c99erfcf(),erfcl(): _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600|| _ISOC99_SOURCE; orcc-std=c99DESCRIPTIONTheerfc() function returns the complementary error function ofx, that is, 1.0 - erf(x).RETURNVALUEOn success, these functions return the complementary error function ofx, a value in the range [0,2]. Ifxis a NaN, a NaN is returned. Ifxis +0 or -0, 1 is returned. Ifxis positive infinity, +0 is returned. Ifxis negative infinity, +2 is returned. If the function result underflows and produces an unrepresentable value, the return value is 0.0. If the function result underflows but produces a representable (i.e., subnormal) value, that value is returned, and a range error occurs.ERRORSSee math_error(7) for information on how to determine whether an error has occurred when calling these func- tions. The following errors can occur: Range error: result underflow (result is subnormal) An underflow floating-point exception (FE_UNDERFLOW) is raised. These functions do not seterrno.CONFORMINGTOC99, POSIX.1-2001. The variant returningdoublealso conforms to SVr4, 4.3BSD.NOTESTheerfc() functions are provided to avoid the loss accuracy that would occur for the calculation 1-erf(x) for large values ofx(for which the value of erf(x) approaches 1).SEEALSOcerf(3), erf(3), exp(3)COLOPHONThis page is part of release 3.22 of the Linuxman-pagesproject. A description of the project, and informa- tion about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/. GNU 2008-08-05 ERFC(3)