.TH _toupper() "" "" "ctype Function (libc)"
.PC "Convert characters to upper case"
\fB#include <ctype.h>\fR
\fBint _toupper(\fIc\^\fB) int \fIc\^\fB;\fR
.PP
The function
\fB_toupper()\fR
converts the character
.I c
to upper case and returns the converted character.
Unlike the related function
.BR toupper() ,
.B _toupper()
is not guaranteed to work correctly if it is passed something other than
a lower-case character, that is, any character for which \fBislower()\fR
returns true.
.SH "See Also"
.Xr "_tolower()," _5Ftolowe
.Xr "libc," libc
.Xr "toupper()" toupper
.SH Notes
.B _toupper()
is not part of the ANSI standard; \*(CO includes it only to support old code.
You should use
.BR toupper()
instead.
