1.\" Copyright (c) 1991 The Regents of the University of California. 2.\" All rights reserved. 3.\" 4.\" %sccs.include.redist.man% 5.\" 6.\" @(#)isalpha.3 5.1 (Berkeley) 05/02/91 7.\" 8.Dd 9.Dt ISALPHA 3 10.Os 11.Sh NAME 12.Nm isalpha 13.Nd alphabetic character test 14.Sh SYNOPSIS 15.Fd #include <ctype.h> 16.Ft int 17.Fn isalpha "int c" 18.Sh DESCRIPTION 19The 20.Fn isalpha 21function tests for any character for which 22.Xr isupper 3 23or 24.Xr islower 3 25is true and 26.\" , or any of an implementation-defined set of characters 27for which none of 28.Xr iscntrl 3 , 29.Xr isdigit 3 , 30.Xr ispunct 3 , 31or 32.Xr isspace 3 33is true. 34In the 35.Em ``C'' 36locale, 37.Fn isalpha 38returns true only for the characters for which 39.Xr isupper 3 40or 41.Xr islower 3 42is true. 43.Sh RETURN VALUES 44The 45.Fn isalpha 46macro returns zero if the character tests false and 47returns non-zero if the character tests true. 48.Sh SEE ALSO 49.Xr isascii 3 , 50.Xr isalnum 3 , 51.Xr iscntrl 3 , 52.Xr isdigit 3 , 53.Xr isgraph 3 , 54.Xr islower 3 , 55.Xr isprint 3 , 56.Xr ispunct 3 , 57.Xr isspace 3 , 58.Xr isupper 3 , 59.Xr isxdigit 3 , 60.Xr toascii 3 , 61.Xr tolower 3 , 62.Xr toupper 3 , 63.Xr stdio 3 64.Xr ascii 7 65.Sh STANDARDS 66The 67.Fn isalpha 68function conforms to 69.St -ansiC . 70