Provided by: manpages-posix-dev_2.16-1_all 
NAME
ctype.h - character types
SYNOPSIS
#include <ctype.h>
DESCRIPTION
Some of the functionality described on this reference page extends the ISO C standard. Applications shall
define the appropriate feature test macro (see the System Interfaces volume of IEEE Std 1003.1-2001,
Section 2.2, The Compilation Environment) to enable the visibility of these symbols in this header.
The following shall be declared as functions and may also be defined as macros. Function prototypes shall
be provided.
int isalnum(int);
int isalpha(int);
int isascii(int);
int isblank(int);
int iscntrl(int);
int isdigit(int);
int isgraph(int);
int islower(int);
int isprint(int);
int ispunct(int);
int isspace(int);
int isupper(int);
int isxdigit(int);
int toascii(int);
int tolower(int);
int toupper(int);
The following are defined as macros:
int _toupper(int);
int _tolower(int);
The following sections are informative.
APPLICATION USAGE
None.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSO
<locale.h> , the System Interfaces volume of IEEE Std 1003.1-2001, isalnum(), isalpha(), isascii(),
iscntrl(), isdigit(), isgraph(), islower(), isprint(), ispunct(), isspace(), isupper(), isxdigit(),
mblen(), mbstowcs(), mbtowc(), setlocale(), toascii(), tolower(), _tolower(), toupper(), _toupper(),
wcstombs(), wctomb()
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition,
Standard for Information Technology -- 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 .