[PATCH] new Page: isalpha__3(3)

[walter harms]

Hi List,
The ctype macros like  isalpha(3) have a locale specific counterpart.
This page was missing.

re,
 wh


Signed-off-by: wharms@xxxxxx <wharms@xxxxxx>


.\" Copyright (c) 2013 by Walter Harms
.\"
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.TH ISALPHA_L 3 2013-09-20 "GNU" "Linux Programmer's Manual"
.SH NAME
isalnum_l, isalpha_l, isblank_l, iscntrl_l, isdigit_l, isgraph_l, islower_l,
isprint_l, ispunct_l, isspace_l, isupper_l, isxdigit_l \- character
classification routines
.SH SYNOPSIS
.nf
.B #include <ctype.h>
.sp
.BI "int isalnum_l(int " "c" ", locale_t " loc );
.br
.BI "int isalpha_l(int " "c" ", locale_t " loc );
.br
.BI "int isascii_l(int " "c" ", locale_t " loc );
.br
.BI "int isblank_l(int " "c" ", locale_t " loc );
.br
.BI "int iscntrl_l(int " "c" ", locale_t " loc );
.br
.BI "int isdigit_l(int " "c" ", locale_t " loc );
.br
.BI "int isgraph_l(int " "c" ", locale_t " loc );
.br
.BI "int islower_l(int " "c" ", locale_t " loc );
.br
.BI "int isprint_l(int " "c" ", locale_t " loc );
.br
.BI "int ispunct_l(int " "c" ", locale_t " loc );
.br
.BI "int isspace_l(int " "c" ", locale_t " loc );
.br
.BI "int isupper_l(int " "c" ", locale_t " loc );
.br
.BI "int isxdigit_l(int " "c" ", locale_t " loc );
.fi
.sp
.SH DESCRIPTION
These functions check whether
.IR c ,
which must have the value of an
.I unsigned char
or
.BR EOF ,
falls into a certain character class according to the current locale.
.TP
.BR isalnum_l ()
checks for an alphanumeric character; it is equivalent to
.BI "(isalpha(" c ") || isdigit(" c "))" \fR.
.TP
.BR isalpha_l ()
checks for an alphabetic character; in the standard \fB"C"\fP
locale, it is equivalent to
.BI "(isupper_l(" c ") || islower_l(" c "))" \fR.
In some locales, there may be additional characters for which
.BR isalpha ()
is true\(emletters which are neither upper case nor lower
case.
.TP
.BR isascii_l ()
checks whether \fIc\fP is a 7-bit
.I unsigned char
value that fits into
the ASCII character set.
.TP
.BR isblank_l ()
checks for a blank character; that is, a space or a tab.
.TP
.BR iscntrl_l ()
checks for a control character.
.TP
.BR isdigit_l ()
checks for a digit (0 through 9).
.TP
.BR isgraph_l ()
checks for any printable character except space.
.TP
.BR islower_l ()
checks for a lower-case character.
.TP
.BR isprint_l ()
checks for any printable character including space.
.TP
.BR ispunct_l ()
checks for any printable character which is not a space or an
alphanumeric character.
.TP
.BR isspace_l ()
checks for white-space characters.
In the
.B """C"""
and
.B """POSIX"""
locales, these are: space, form-feed
.RB ( \(aq\ef\(aq ),
newline
.RB ( \(aq\en\(aq ),
carriage return
.RB ( \(aq\er\(aq ),
horizontal tab
.RB ( \(aq\et\(aq ),
and vertical tab
.RB ( \(aq\ev\(aq ).
.TP
.BR isupper_l ()
checks for an uppercase letter.
.TP
.BR isxdigit_l ()
checks for a hexadecimal digits, that is, one of
.br
.BR "0 1 2 3 4 5 6 7 8 9 a b c d e f A B C D E F" .
.SH RETURN VALUE
The values returned are nonzero if the character
.I c
falls into the tested class, and a zero value
if not.
.SH CONFORMING TO
POSIX.1-2008 specifies all of these functions.
.SH NOTES
The details of what characters belong into which class depend on the current
locale.
.sp
from
.IR locale.h :
The concept of one static locale per category is not very well
thought out.  Many applications will need to process its data using
information from several different locales.  Another application is
the implementation of the internationalization handling in the
upcoming ISO C++ standard library.  To support this another set of
the functions using locale data exist which have an additional
argument.

For example,
.BR isupper ()
will not recognize an A-umlaut (\(:A) as an uppercase letter in the default
.B "C"
locale.
.SH EXAMPLE
The following example takes a locale abbreviation like "de_DE" as argument.
Is no argument is supplied it will use "C". With "de_DE" the code will
identify the O-Umlaut correctly as alphanumeric character but not with "C".
In contrast the punctuation will perform as before.
.nf

#include <stdio.h>
#include <locale.h>

int main(int argc,char *argv[])
{
  char *str="c2p\(:O.,";
  int i;
  locale_t loc;
    if (argc > 1 )
      loc = newlocale (LC_ALL_MASK, argv[1], NULL);
    else
      loc = newlocale (LC_ALL_MASK, "C", NULL);

  for(i=0;str[i]!=0;i++) {
    if (isalnum_l(str[i],loc))
	printf("The character %c is alphanumeric.\\n",str[i]);
    if ( ispunct_l(str[i],loc) )
	printf ("The character %c is punctuation.\\n",str[i]);
  }
  return 0;
}

.fi
.SH SEE ALSO
.BR iswalnum (3),
.BR iswalpha (3),
.BR iswblank (3),
.BR iswcntrl (3),
.BR iswdigit (3),
.BR iswgraph (3),
.BR iswlower (3),
.BR iswprint (3),
.BR iswpunct (3),
.BR iswspace (3),
.BR iswupper (3),
.BR iswxdigit (3),
.BR setlocale (3),
.BR toascii (3),
.BR tolower (3),
.BR toupper (3),
.BR ascii (7),
.BR locale (7)
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