Manual Pages  — ISUPPER

isupper, isupper_l – upper-case character test

LIBRARY SYNOPSIS DESCRIPTION RETURN VALUES COMPATIBILITY SEE ALSO STANDARDS HISTORY

Standard C Library (libc, -lc)

#include <ctype.h>

int
isupper(int c);

int
isupper_l(int c, locale_t loc);

The isupper() and isupper_l() functions test 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_l() function takes an explicit locale argument, whereas the isupper() function uses the current global or per-thread locale.

The isupper() and isupper_l() functions return zero if the character tests false and return 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() or iswupper_l() function should be used instead.

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

The isupper() function first appeared in AT&T v7 .