Guardian Native C Library Calls Reference Manual (G06.28+, H06.05+)

Guardian Native C Library Calls (g - i) isalnum(3)
NAME
isalnum - Tests for an alphanumeric character
LIBRARY
G-series native Guardian processes: $SYSTEM.SYSnn.ZCRTLSRL
G-series native OSS processes: /G/system/sysnn/zcrtlsrl
H-series native Guardian processes: $SYSTEM.ZDLLnnn.ZCRTLDLL
H-series OSS processes: /G/system/zdllnnn/zcrtldll
SYNOPSIS
#include <ctype.h>
int isalnum(
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 alphanumeric character class in the current locale. If
the character is part of the character class, the function returns a nonzero value for true; other-
wise, it returns a value of 0 (zero) for false.
The function returns a true value when c is a character of class alpha or class digit in the
program’s current locale.
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: isalpha(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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