toascii, tolower, _tolower, toupper, _toupper - Translate
characters
#include <ctype.h>
int toascii(
int c ); int tolower(
int c ); int _tolower(
int c ); int toupper(
int c ); int _toupper(
int c );
Standard C Library (libc)
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.
Specifies the character to be converted.
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.
The LC_CTYPE category of the current locale affects all
conversions. See the i18n_intro(5) reference page for more
information on locale variables.
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.
Functions: ctype(3)
Other: i18n_intro(5), standards(5)
conv(3)
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