Manual Pages  — ISUPPER

isupper – upper-case character test

LIBRARY SYNOPSIS DESCRIPTION RETURN VALUES COMPATIBILITY SEE ALSO STANDARDS

Standard C Library (libc, -lc)

#include <ctype.h>

int
isupper(int c);

The isupper() function tests for any upper-case letter. The value of the argument must be representable as an unsigned char or the value of EOF.

In the ASCII character set, this includes the following characters (with their numeric values shown in octal):

amp;101 ``A''	102 ``B''	103 ``C''	104 ``D''	105 ``E''
amp;106 ``F''	107 ``G''	110 ``H''	111 ``I''	112 ``J''
amp;113 ``K''	114 ``L''	115 ``M''	116 ``N''	117 ``O''
amp;120 ``P''	121 ``Q''	122 ``R''	123 ``S''	124 ``T''
amp;125 ``U''	126 ``V''	127 ``W''	130 ``X''	131 ``Y''
amp;132 ``Z''	amp;	amp;	amp;	amp;

The isupper() function returns zero if the character tests false and returns non-zero if the character tests true.

The BSD 4.4 extension of accepting arguments outside of the range of the unsigned char type in locales with large character sets is considered obsolete and may not be supported in future releases. The iswupper() function should be used instead.

The isupper() function conforms to ISO/IEC 9899:1990 ("ISO C90").