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ISBLANK(3) Library Functions Manual ISBLANK(3)

isblankblank-space character test

#include <ctype.h>

int
isblank(int c);

The () function tests for the standard blank-space characters. The standard blank-space characters are the following:

‘ ’
Space character.
Horizontal tab.

In the C locale, () returns true only for the standard blank-space characters.

The isblank() function returns zero if the character tests false or non-zero if the character tests true.

isalnum(3), isalpha(3), isascii(3), iscntrl(3), isdigit(3), isgraph(3), islower(3), isprint(3), ispunct(3), isspace(3), isupper(3), isxdigit(3), stdio(3), toascii(3), tolower(3), toupper(3), ascii(7)

The isblank() function conforms to ISO/IEC 9899:1999 (“ISO C99”).

The argument to isblank() must be EOF or representable as an unsigned char; otherwise, the result is undefined.

June 23, 2015 OpenBSD-5.9