conv(3C)

NAME

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 domain the range of getc(3S): the integers from -1 through 255. 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. Arguments outside the domain cause undefined results.

The macros _toupper() and _tolower() are identical to toupper() and tolower(), respectively.

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

WARNINGS

toascii() is supplied both as a library function and as a macro defined in the <ctype.h> header. Normally, the macro version is used. To obtain the library function, either use a #undef to remove the macro definition or, if compiling in ANSI C mode, enclose the function name in parenthesis or take its address. The following examples use the library function for toascii():

#include <ctype.h> 
#undef toascii 
       ...
main() 
{ 
       ...
    c1 = toascii(c); 
       ...
} 

#include <ctype.h> 
       ...
main() 
{ 
   int (*conv_func)(); 
       ...
   c1 = (toascii)(c); 
       ...
   conv_func = toascii; 
       ...
} 

The following example use the library function for toupper():

#include <ctype.h> 
#undef toupper 
       ...
main() 
{ 
       ...
char *c; 
*c=toupper ((unsigned char*) c); 
       ...
} 

EXTERNAL INFLUENCES

Locale

The LC_CTYPE category determines the translations to be done.

International Code Set Support

Single-byte character code sets are supported.

AUTHOR

conv() was developed by IBM, OSF, and HP.

STANDARDS CONFORMANCE

_tolower(): AES, SVID2, SVID3, XPG2, XPG3, XPG4

_toupper(): AES, SVID2, SVID3, XPG2, XPG3, XPG4

toascii(): AES, SVID2, SVID3, XPG2, XPG3, XPG4

tolower(): AES, SVID2, SVID3, XPG2, XPG3, XPG4, FIPS 151-2, POSIX.1, ANSI C

toupper(): AES, SVID2, SVID3, XPG2, XPG3, XPG4, FIPS 151-2, POSIX.1, ANSI C