islower(3p) [suse man page]
ISLOWER(3P) POSIX Programmer's Manual ISLOWER(3P) PROLOG
This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the correspond- ing Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux. NAME
islower - test for a lowercase letter SYNOPSIS
#include <ctype.h> int islower(int c); DESCRIPTION
The islower() function shall test whether c is a character of class lower in the program's current locale; see the Base Definitions volume of IEEE Std 1003.1-2001, Chapter 7, Locale. The c argument is an int, the value of which the application shall ensure is a character representable as an unsigned char or equal to the value of the macro EOF. If the argument has any other value, the behavior is undefined. RETURN VALUE
The islower() function shall return non-zero if c is a lowercase letter; otherwise, it shall return 0. ERRORS
No errors are defined. The following sections are informative. EXAMPLES
Testing for a Lowercase Letter The following example tests whether the value is a lowercase letter, based on the locale of the user, then uses it as part of a key value. #include <ctype.h> #include <stdlib.h> #include <locale.h> ... char *keystr; int elementlen, len; char c; ... setlocale(LC_ALL, ""); ... len = 0; while (len < elementlen) { c = (char) (rand() % 256); ... if (islower(c)) keystr[len++] = c; } ... APPLICATION USAGE
To ensure applications portability, especially across natural languages, only this function and those listed in the SEE ALSO section should be used for character classification. RATIONALE
None. FUTURE DIRECTIONS
None. SEE ALSO
isalnum(), isalpha(), iscntrl(), isdigit(), isgraph(), isprint(), ispunct(), isspace(), isupper(), isxdigit(), setlocale(), the Base Defi- nitions volume of IEEE Std 1003.1-2001, Chapter 7, Locale, <ctype.h> COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technol- ogy -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html . IEEE
/The Open Group 2003 ISLOWER(3P)
Check Out this Related Man Page
ISLOWER(3P) POSIX Programmer's Manual ISLOWER(3P) PROLOG
This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the correspond- ing Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux. NAME
islower, islower_l -- test for a lowercase letter SYNOPSIS
#include <ctype.h> int islower(int c); int islower_l(int c, locale_t locale); DESCRIPTION
For islower(): The functionality described on this reference page is aligned with the ISO C standard. Any conflict between the requirements described here and the ISO C standard is unintentional. This volume of POSIX.1-2008 defers to the ISO C standard. The islower() and islower_l() functions shall test whether c is a character of class lower in the current locale, or in the locale repre- sented by locale, respectively; see the Base Definitions volume of POSIX.1-2008, Chapter 7, Locale. The c argument is an int, the value of which the application shall ensure is a character representable as an unsigned char or equal to the value of the macro EOF. If the argument has any other value, the behavior is undefined. The behavior is undefined if the locale argument to islower_l() is the special locale object LC_GLOBAL_LOCALE or is not a valid locale object handle. RETURN VALUE
The islower() and islower_l() functions shall return non-zero if c is a lowercase letter; otherwise, they shall return 0. ERRORS
No errors are defined. The following sections are informative. EXAMPLES
Testing for a Lowercase Letter Two examples follow, the first using islower(), the second using multiple concurrent locales and islower_l(). The examples test whether the value is a lowercase letter, based on the current locale, then use it as part of a key value. /* Example 1 -- using islower() */ #include <ctype.h> #include <stdlib.h> #include <locale.h> ... char *keystr; int elementlen, len; unsigned char c; ... setlocale(LC_ALL, ""); ... len = 0; while (len < elementlen) { c = (unsigned char) (rand() % 256); ... if (islower(c)) keystr[len++] = c; } ... /* Example 2 -- using islower_l() */ #include <ctype.h> #include <stdlib.h> #include <locale.h> ... char *keystr; int elementlen, len; unsigned char c; ... locale_t loc = newlocale (LC_ALL_MASK, "", (locale_t) 0); ... len = 0; while (len < elementlen) { c = (unsigned char) (rand() % 256); ... if (islower_l(c, loc)) keystr[len++] = c; } ... APPLICATION USAGE
To ensure applications portability, especially across natural languages, only these functions and the functions in the reference pages listed in the SEE ALSO section should be used for character classification. RATIONALE
None. FUTURE DIRECTIONS
None. SEE ALSO
isalnum(), isalpha(), isblank(), iscntrl(), isdigit(), isgraph(), isprint(), ispunct(), isspace(), isupper(), isxdigit(), setlocale(), use- locale() The Base Definitions volume of POSIX.1-2008, Chapter 7, Locale, <ctype.h>, <locale.h> COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2013 Edition, Standard for Information Technol- ogy -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 7, Copyright (C) 2013 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Stan- dard is the referee document. The original Standard can be obtained online at http://www.unix.org/online.html . Any typographical or formatting errors that appear in this page are most likely to have been introduced during the conversion of the source files to man page format. To report such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html . IEEE
/The Open Group 2013 ISLOWER(3P)