1*d790b16bSRobert Clausecker.\" 2*d790b16bSRobert Clausecker.\" Copyright (c) 2025 Robert Clausecker <fuz@FreeBSD.org> 3*d790b16bSRobert Clausecker.\" 4*d790b16bSRobert Clausecker.\" SPDX-License-Identifier: BSD-2-Clause 5*d790b16bSRobert Clausecker.\" 6*d790b16bSRobert Clausecker.Dd November 9, 2025 7*d790b16bSRobert Clausecker.Dt STDC_TRAILING_ZEROS 3 8*d790b16bSRobert Clausecker.Os 9*d790b16bSRobert Clausecker.Sh NAME 10*d790b16bSRobert Clausecker.Nm stdc_trailing_zeros 11*d790b16bSRobert Clausecker.Nd find the number of trailing zeros in an integer 12*d790b16bSRobert Clausecker.Sh SYNOPSIS 13*d790b16bSRobert Clausecker.Lb libc 14*d790b16bSRobert Clausecker.In stdbit.h 15*d790b16bSRobert Clausecker.Ft unsigned int 16*d790b16bSRobert Clausecker.Fn stdc_trailing_zeros_uc "unsigned char value" 17*d790b16bSRobert Clausecker.Ft unsigned int 18*d790b16bSRobert Clausecker.Fn stdc_trailing_zeros_us "unsigned short value" 19*d790b16bSRobert Clausecker.Ft unsigned int 20*d790b16bSRobert Clausecker.Fn stdc_trailing_zeros_ui "unsigned int value" 21*d790b16bSRobert Clausecker.Ft unsigned int 22*d790b16bSRobert Clausecker.Fn stdc_trailing_zeros_ul "unsigned long value" 23*d790b16bSRobert Clausecker.Ft unsigned int 24*d790b16bSRobert Clausecker.Fn stdc_trailing_zeros_ull "unsigned long long value" 25*d790b16bSRobert Clausecker.Ft unsigned int 26*d790b16bSRobert Clausecker.Fn stdc_trailing_zeros "value" 27*d790b16bSRobert Clausecker.Sh DESCRIPTION 28*d790b16bSRobert ClauseckerThe 29*d790b16bSRobert Clausecker.Nm stdc_trailing_zeros_ Ns Em type Ns () 30*d790b16bSRobert Clauseckerfamily of functions returns the number of trailing zeros in 31*d790b16bSRobert Clausecker.Fa value , 32*d790b16bSRobert Clauseckerwhere 33*d790b16bSRobert Clausecker.Fa value 34*d790b16bSRobert Clauseckeris of type 35*d790b16bSRobert Clausecker.Va unsigned char , 36*d790b16bSRobert Clausecker.Va unsigned short , 37*d790b16bSRobert Clausecker.Va unsigned int , 38*d790b16bSRobert Clausecker.Va unsigned long , 39*d790b16bSRobert Clauseckeror 40*d790b16bSRobert Clausecker.Va unsigned long long 41*d790b16bSRobert Clauseckerfor 42*d790b16bSRobert Clausecker.Em type 43*d790b16bSRobert Clauseckerbeing 44*d790b16bSRobert Clausecker.Sy uc , 45*d790b16bSRobert Clausecker.Sy us , 46*d790b16bSRobert Clausecker.Sy ui , 47*d790b16bSRobert Clausecker.Sy ul , 48*d790b16bSRobert Clauseckeror 49*d790b16bSRobert Clausecker.Sy ull 50*d790b16bSRobert Clauseckerrespectively. 51*d790b16bSRobert ClauseckerThe 52*d790b16bSRobert Clausecker.Fn stdc_trailing_zeros "value" 53*d790b16bSRobert Clauseckertype-generic macro picks the appropriate 54*d790b16bSRobert Clausecker.Nm stdc_trailing_zeros_ Ns Em type Ns () 55*d790b16bSRobert Clauseckerfunction based on the type of 56*d790b16bSRobert Clausecker.Fa value . 57*d790b16bSRobert Clausecker.Sh RETURN VALUES 58*d790b16bSRobert ClauseckerReturns the number of trailing zeros in 59*d790b16bSRobert Clausecker.Fa value . 60*d790b16bSRobert ClauseckerIf 61*d790b16bSRobert Clausecker.Fa value 62*d790b16bSRobert Clauseckeris all zeros, 63*d790b16bSRobert Clauseckerthe total number of bits in the type of 64*d790b16bSRobert Clausecker.Fa value 65*d790b16bSRobert Clauseckeris returned. 66*d790b16bSRobert Clausecker.Sh SEE ALSO 67*d790b16bSRobert Clausecker.Xr ffs 3 , 68*d790b16bSRobert Clausecker.Xr stdbit 3 , 69*d790b16bSRobert Clausecker.Xr stdc_leading_zeros 3 , 70*d790b16bSRobert Clausecker.Xr stdc_trailing_ones 3 , 71*d790b16bSRobert Clausecker.Xr stdc_first_trailing_one 3 72*d790b16bSRobert Clausecker.Sh STANDARDS 73*d790b16bSRobert ClauseckerThe 74*d790b16bSRobert Clausecker.Nm stdc_trailing_zeros_ Ns Em type Ns () 75*d790b16bSRobert Clauseckerfamily of functions and the 76*d790b16bSRobert Clausecker.Fn stdc_trailing_zeros 77*d790b16bSRobert Clauseckertype-generic macro conform to 78*d790b16bSRobert Clausecker.St -isoC-2023 . 79*d790b16bSRobert Clausecker.Sh HISTORY 80*d790b16bSRobert ClauseckerThe 81*d790b16bSRobert Clausecker.Nm stdc_trailing_zeros_ Ns Em type Ns () 82*d790b16bSRobert Clauseckerfamily of functions and the 83*d790b16bSRobert Clausecker.Fn stdc_trailing_zeros 84*d790b16bSRobert Clauseckertype-generic macro were added in 85*d790b16bSRobert Clausecker.Fx 15.1. 86*d790b16bSRobert Clausecker.Sh AUTHOR 87*d790b16bSRobert Clausecker.An Robert Clausecker Aq Mt fuz@FreeBSD.org 88