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conv

Section: C Library Functions (3)
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NAME

toascii, tolower, _tolower, toupper, _toupper - Translate characters  

LIBRARY

Standard C Library (libc.so, libc.a)  

SYNOPSIS

#include <ctype.h>

int toascii(
        int c);

int tolower(
        int c);

int _tolower(
        int c);

int toupper(
        int c);

int _toupper(
        int c);  

STANDARDS

Interfaces documented on this reference page conform to industry standards as follows:

toascii(), tolower(), _tolower(), toupper(), _toupper():  XPG4, XPG4-UNIX

Refer to the standards(5) reference page for more information about industry standards and associated tags.  

PARAMETERS

Specifies the character to be converted.  

DESCRIPTION

The toascii(), tolower(), _tolower(), toupper(), and _toupper() functions translate all characters, including multibyte characters, to their specified character values.

The toascii() function converts its input to a 7-bit ASCII character.

The tolower() function takes an int value that can be represented as an unsigned char or the value of EOF (defined in the stdio.h header file) as its input.

When the input of the tolower() function expresses an uppercase letter, and there exists a corresponding lowercase letter (as defined by character type information in the program locale category LC_CTYPE), the corresponding lowercase letter is returned. All other input values in the domain are returned unchanged. The tolower() function has as its domain the range -1 through 255.

In the C locale, or in a locale where case-conversion information is not defined, the tolower() function determines the case of characters according to the rules of the Portable Character Set (ASCII characters). Characters outside the ASCII range of characters are returned unchanged.

The _tolower() macro is equivalent to the tolower() function, but executes faster. If the value of the c parameter to the _tolower() macro does not have a corresponding lowercase character, the results of the function are undefined.

The toupper() function takes an int value that can be represented as an unsigned char or the value of EOF (defined in the stdio.h header file) as its input.

When the input of the toupper() function expresses a lowercase letter, and there exists a corresponding uppercase letter (as defined by character type information in the program locale category LC_CTYPE), the corresponding uppercase letter is returned. All other input values in the domain are returned unchanged. The toupper() function has as its domain the range -1 through 255.

In the C locale, or in a locale where case-conversion information is not defined, the toupper() function determines the case of characters according to the rules of the Portable Character Set (ASCII characters). Characters outside the ASCII range of characters are returned unchanged.

The _toupper() macro is equivalent to the toupper() function, but executes faster. If the value of the c parameter to the _toupper() macro does not have a corresponding uppercase character, the results of the function are undefined.  

NOTES

The LC_CTYPE category of the current locale affects all conversions. See the i18n_intro(5) reference page for more information on locale variables.  

RETURN VALUES

The toascii() function returns the logical AND of parameter c and the value 0X7F.

When the c parameter is a character for which the isupper() function is TRUE, there is a corresponding character for which the islower() function is also TRUE. That lowercase character is returned by the tolower() function or by the _tolower() macro. Otherwise, the c parameter is returned unchanged.

When the c parameter is a character for which the islower() function is TRUE, there is a corresponding character for which the isupper() function is also TRUE. That uppercase character is returned by the toupper() function or by the _toupper() macro. Otherwise, the c parameter is returned unchanged.  

RELATED INFORMATION

Functions: ctype(3)

Other: i18n_intro(5), standards(5) delim off


 

Index

NAME
LIBRARY
SYNOPSIS
STANDARDS
PARAMETERS
DESCRIPTION
NOTES
RETURN VALUES
RELATED INFORMATION

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Time: 02:41:42 GMT, October 02, 2010