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);

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

  —  C Programming Language Utilities