7.4.1 Character classification functions
1 The functions in this subclause return nonzero (true) if and only if the value of the
argument c conforms to that in the description of the function.
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7.4.1.3 The isblank function
Synopsis
1 #include <ctype.h>
int isblank(int c);
Description
2 The isblank function tests for any character that is a standard blank character or is one
of a locale-specific set of characters for which isspace is true and that is used to
separate words within a line of text. The standard blank characters are the following:
space (' '), and horizontal tab ('\t'). In the "C" locale, isblank returns true only
for the standard blank characters.
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7.4.1.10 The isspace function
Synopsis
1 #include <ctype.h>
int isspace(int c);
Description
2 The isspace function tests for any character that is a standard white-space character or
is one of a locale-specific set of characters for which isalnum is false. The standard white-space characters are the following: space (' '), form feed ('\f'), new-line
('\n'), carriage return ('\r'), horizontal tab ('\t'), and vertical tab ('\v'). In the
"C" locale, isspace returns true only for the standard white-space characters.