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ISLOWER(3) FreeBSD Library Functions Manual ISLOWER(3)
NAME
islower, islower_l - lower-case character test
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <ctype.h>
int
islower(int c);
int
islower_l(int c, locale_t loc);
DESCRIPTION
The islower() and islower_l() functions test for any lower-case letters.
The value of the argument must be representable as an unsigned char or
the value of EOF.
In the ASCII character set, this includes the following characters (with
their numeric values shown in octal):
141 ``a'' 142 ``b'' 143 ``c'' 144 ``d'' 145 ``e''
146 ``f'' 147 ``g'' 150 ``h'' 151 ``i'' 152 ``j''
153 ``k'' 154 ``l'' 155 ``m'' 156 ``n'' 157 ``o''
160 ``p'' 161 ``q'' 162 ``r'' 163 ``s'' 164 ``t''
165 ``u'' 166 ``v'' 167 ``w'' 170 ``x'' 171 ``y''
172 ``z''
The islower_l() function takes an explicit locale argument, whereas the
islower() function uses the current global or per-thread locale.
RETURN VALUES
The islower() and islower_l() functions return zero if the character
tests false and return non-zero if the character tests true.
COMPATIBILITY
The 4.4BSD extension of accepting arguments outside of the range of the
unsigned char type in locales with large character sets is considered
obsolete and may not be supported in future releases. The iswlower() or
iswlower_l() function should be used instead.
SEE ALSO
ctype(3), ctype_l(3), iswlower(3), iswlower_l(3), tolower(3),
tolower_l(3), xlocale(3), ascii(7)
STANDARDS
The islower() function conforms to ISO/IEC 9899:1990 ("ISO C90"). The
islower_l() function conforms to IEEE Std 1003.1-2008 ("POSIX.1").
HISTORY
The islower() function first appeared in Version 7 AT&T UNIX.
FreeBSD 14.0-RELEASE-p6 December 19, 2022 FreeBSD 14.0-RELEASE-p6