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isblank

From cppreference.com
< c‎ | string‎ | byte
 
 
 
Null-terminated byte strings
Functions
Character manipulation
 
Defined in header <ctype.h>
int isblank( int ch );
(since C99)

Checks if the given character is a blank character in the current C locale. In the default C locale, only space (0x20) and horizontal tab (0x09) are classified as blank.

The behavior is undefined if the value of ch is not representable as unsigned char and is not equal to EOF .

[edit] Parameters

ch - character to classify

[edit] Return value

Non-zero value if the character is a blank character, zero otherwise.

[edit] Example

Run this code
#include <ctype.h>
#include <limits.h>
#include <stdio.h>
 
int main(void)
{
 for (int ndx = 0; ndx != UCHAR_MAX ; ++ndx)
 if (isblank(ndx))
 printf ("0x%02x\n", ndx);
}

Output:

0x09
0x20

[edit] References

  • C23 standard (ISO/IEC 9899:2024):
  • 7.4.1.3 The isblank function (p: TBD)
  • C17 standard (ISO/IEC 9899:2018):
  • 7.4.1.3 The isblank function (p: 145)
  • C11 standard (ISO/IEC 9899:2011):
  • 7.4.1.3 The isblank function (p: 201)
  • C99 standard (ISO/IEC 9899:1999):
  • 7.4.1.3 The isblank function (p: 182)

[edit] See also

(C99)
checks if a wide character is a blank character
(function) [edit]
C++ documentation for isblank
ASCII values characters

iscntrl
iswcntrl

isprint
iswprint

isspace
iswspace

isblank
iswblank

isgraph
iswgraph

ispunct
iswpunct

isalnum
iswalnum

isalpha
iswalpha

isupper
iswupper

islower
iswlower

isdigit
iswdigit

isxdigit
iswxdigit

decimal hexadecimal octal
0–8 \x0\x8 0円10円 control codes (NUL, etc.) ≠0 0 0 0 0 0 0 0 0 0 0 0
9 \x9 11円 tab (\t) ≠0 0 ≠0 ≠0 0 0 0 0 0 0 0 0
10–13 \xA\xD 12円15円 whitespaces (\n, \v, \f, \r) ≠0 0 ≠0 0 0 0 0 0 0 0 0 0
14–31 \xE\x1F 16円37円 control codes ≠0 0 0 0 0 0 0 0 0 0 0 0
32 \x20 40円 space 0 ≠0 ≠0 ≠0 0 0 0 0 0 0 0 0
33–47 \x21\x2F 41円57円 !"#$%&'()*+,-./ 0 ≠0 0 0 ≠0 ≠0 0 0 0 0 0 0
48–57 \x30\x39 60円71円 0123456789 0 ≠0 0 0 ≠0 0 ≠0 0 0 0 ≠0 ≠0
58–64 \x3A\x40 72円100円 :;<=>?@ 0 ≠0 0 0 ≠0 ≠0 0 0 0 0 0 0
65–70 \x41\x46 101円106円 ABCDEF 0 ≠0 0 0 ≠0 0 ≠0 ≠0 ≠0 0 0 ≠0
71–90 \x47\x5A 107円132円 GHIJKLMNOP
QRSTUVWXYZ
0 ≠0 0 0 ≠0 0 ≠0 ≠0 ≠0 0 0 0
91–96 \x5B\x60 133円140円 [\]^_` 0 ≠0 0 0 ≠0 ≠0 0 0 0 0 0 0
97–102 \x61\x66 141円146円 abcdef 0 ≠0 0 0 ≠0 0 ≠0 ≠0 0 ≠0 0 ≠0
103–122 \x67\x7A 147円172円 ghijklmnop
qrstuvwxyz
0 ≠0 0 0 ≠0 0 ≠0 ≠0 0 ≠0 0 0
123–126 \x7B\x7E 173円176円 {|}~ 0 ≠0 0 0 ≠0 ≠0 0 0 0 0 0 0
127 \x7F 177円 backspace character (DEL) ≠0 0 0 0 0 0 0 0 0 0 0 0

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