Open System Services Library Calls Reference Manual (G06.29+, H06.08+, J06.03+)

OSS Library Calls (i - m) isalpha(3)
NAME
isalpha - Tests for alphabetic character
LIBRARY
G-series native Guardian processes: $SYSTEM.SYSnn.ZCRTLSRL
G-series native OSS processes: /G/system/sysnn/zcrtlsrl
H-series and J-series native Guardian processes: $SYSTEM.ZDLLnnn.ZCRTLDLL
32-bit H-series and J-series OSS processes: /G/system/zdllnnn/zcrtldll
64-bit H-series and J-series OSS processes: /G/system/zdllnnn/ycrtldll
SYNOPSIS
#include <ctype.h>
int isalpha(
int c);
PARAMETERS
c Specifies the character to be tested. In all cases, this parameter is an int data
type, whose value must be representable as an unsigned char or must equal the
value of the macro EOF (defined in the stdio.h include file). When this parame-
ter has a value that cannot be represented as an unsigned char or EOF, the
result is undefined.
DESCRIPTION
This function tests for membership in the alphabetic character class in the current locale. If the
character is part of the character class, the function returns a nonzero value for true; otherwise, it
returns a value of 0 (zero) for false.
The isalpha( ) function tests whether the character specified by the c parameter belongs to the
alpha class. The function returns a true value when c is a character of class alpha in the
program’s current locale.
Characters in classes lower and upper automatically belong to class alpha.
NOTES
The LC_CTYPE category of the setlocale( ) function affects all conversions.
In the C locale, or in a locale where character-type information is not defined, characters are
classified according to the rules of the US-ASCII 7-bit coded character set. For any character
value greater than octal 177 (0177 in C-language context) the value 0 (zero) is returned.
RETURN VALUES
Upon successful completion of any function, a nonzero (TRUE) value is returned. Otherwise,
the value 0 (FALSE) is returned.
RELATED INFORMATION
Functions: isalnum(3), isascii(3), iscntrl(3), isdigit(3), isgraph(3), islower(3), isprint(3),
ispunct(3), isspace(3), isupper(3), isxdigit(3), setlocale(3).
Files: locale(4).
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