CODEWITHSUNDEEP
ctypesbooleanc99
eonil
eonil

Reputation: 85975

What is the C99 _Bool data type and how do you use it?

What is the C99 _Bool data type and how do you use it?

Upvotes: 99

Views: 76734

Answers (2)

evandrix
evandrix

Reputation: 6210

Please do check out the answer here on this related thread found on DaniWeb.

extracted and quoted here for convenient reference:-

usage of new keywords in c99

_Bool: C99's boolean type. Using _Bool directly is only recommended if you're maintaining legacy code that already defines macros for bool, true, or false. Otherwise, those macros are standardized in the <stdbool.h> header. Include that header and you can use bool just like you would in C++.

#include <stdio.h>
#include <stdbool.h>

int main ( void )
{
  bool b = true;

  if ( b )
    printf ( "Yes\n" );
  else
    printf ( "No\n" );

  return 0;
}

Upvotes: 63

Prasoon Saurav
Prasoon Saurav

Reputation: 92864

Include <stdbool.h> header

#include <stdbool.h>

int main(void){
  bool b = false;
}

Macros true and false expand to 1 and 0 respectively.

Section 7.16 Boolean type and values < stdbool.h >

  • 1 The header <stdbool.h> defines four macros.
  • 2 The macro
    • bool expands to _Bool.
  • 3 The remaining three macros are suitable for use in #if preprocessing directives. They are
    • true : which expands to the integer constant 1,
    • false: which expands to the integer constant 0, and
    • __bool_true_false_are_defined which expands to the integer constant 1.
  • 4 Notwithstanding the provisions of 7.1.3, a program may undefine and perhaps then redefine the macros bool, true, and false.

Upvotes: 125

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