1.\" Copyright (c) 1991 The Regents of the University of California. 2.\" All rights reserved. 3.\" 4.\" This code is derived from software contributed to Berkeley by 5.\" the American National Standards Committee X3, on Information 6.\" Processing Systems. 7.\" 8.\" %sccs.include.redist.man% 9.\" 10.\" @(#)isalpha.3 5.2 (Berkeley) 06/29/91 11.\" 12.Dd 13.Dt ISALPHA 3 14.Os 15.Sh NAME 16.Nm isalpha 17.Nd alphabetic character test 18.Sh SYNOPSIS 19.Fd #include <ctype.h> 20.Ft int 21.Fn isalpha "int c" 22.Sh DESCRIPTION 23The 24.Fn isalpha 25function tests for any character for which 26.Xr isupper 3 27or 28.Xr islower 3 29is true and 30.\" , or any of an implementation-defined set of characters 31for which none of 32.Xr iscntrl 3 , 33.Xr isdigit 3 , 34.Xr ispunct 3 , 35or 36.Xr isspace 3 37is true. 38In the 39.Em ``C'' 40locale, 41.Fn isalpha 42returns true only for the characters for which 43.Xr isupper 3 44or 45.Xr islower 3 46is true. 47.Sh RETURN VALUES 48The 49.Fn isalpha 50macro returns zero if the character tests false and 51returns non-zero if the character tests true. 52.Sh SEE ALSO 53.Xr isascii 3 , 54.Xr isalnum 3 , 55.Xr iscntrl 3 , 56.Xr isdigit 3 , 57.Xr isgraph 3 , 58.Xr islower 3 , 59.Xr isprint 3 , 60.Xr ispunct 3 , 61.Xr isspace 3 , 62.Xr isupper 3 , 63.Xr isxdigit 3 , 64.Xr toascii 3 , 65.Xr tolower 3 , 66.Xr toupper 3 , 67.Xr stdio 3 68.Xr ascii 7 69.Sh STANDARDS 70The 71.Fn isalpha 72function conforms to 73.St -ansiC . 74