NAME

conv, toupper, tolower, _toupper, _tolower, toascii - translate characters

SYNOPSIS

#include <ctype.h>

int toupper(int c);
int tolower(int c);
int _toupper(int c);
int _tolower(int c);
int toascii(int c);

MT-LEVEL

MT-Safe with exceptions

DESCRIPTION

toupper( ) and tolower( ) have as their domain the range of the function getc( ): all values represented in an unsigned char and the value of the macro EOF as defined in stdio.h. If the argument of toupper( ) represents a lower-case letter, the result is the corresponding upper-case letter. If the argument of tolower( ) represents an upper-case letter, the result is the corresponding lower-case letter. All other arguments in the domain are returned unchanged.

The macros _toupper( ) and _tolower( ) accomplish the same things as toupper( ) and tolower( ), respectively, but have restricted domains and are faster. _toupper( ) requires a lower-case letter as its argument; its result is the corresponding upper-case letter. _tolower( ) requires an upper-case letter as its argument; its result is the corresponding lower-case letter. Arguments outside the domain cause undefined results.

toascii( ) yields its argument with all bits turned off that are not part of a standard 7-bit ASCII character; it is intended for compatibility with other systems.

toupper( ), tolower( ), _toupper( ), and _tolower( ) are affected by LC_CTYPE . In the "C" locale, or in a locale where shift information is not defined, these functions determine the case of characters according to the rules of the ASCII-coded character set. Characters outside the ASCII range of characters are returned unchanged.

SEE ALSO

ctype(3C), setlocale(3C), getc(3S), environ(5)

NOTES

toupper, tolower ,_toupper, _tolower and toascii can be used safely in a multi-thread application, as long as setlocale(3C) is not being called to change the locale.