The Open Group Base Specifications Issue 7
IEEE Std 1003.1-2008, 2016 Edition
Copyright © 2001-2016 The IEEE and The Open Group

#### NAME

> isspace, isspace_l - test for a white-space character

#### SYNOPSIS

> ``#include <ctype.h>
> int isspace(int` c`);
> ``

> ``[CX] int isspace_l(int` c`, locale_t` locale`);``
> `
> `

#### DESCRIPTION

> For isspace(): [CX] The functionality described on this reference page is aligned with the ISO C standard. Any conflict between the requirements described here and the ISO C standard is unintentional. This volume of POSIX.1-2008 defers to the ISO C standard.

> The isspace() [CX] and isspace_l() functions shall test whether c is a character of class space in the current locale, [CX] or in the locale represented by locale, respectively; see XBD Locale.

> The c argument is an int, the value of which the application shall ensure is a character representable as an unsigned char or equal to the value of the macro EOF. If the argument has any other value, the behavior is undefined.

> [CX] The behavior is undefined if the locale argument to isspace_l() is the special locale object LC_GLOBAL_LOCALE or is not a valid locale object handle.

#### RETURN VALUE

> The isspace() [CX] and isspace_l() functions shall return non-zero if c is a white-space character; otherwise, they shall return 0.

#### ERRORS

> No errors are defined.

The following sections are informative.

#### EXAMPLES

> None.

#### APPLICATION USAGE

> To ensure applications portability, especially across natural languages, only these functions and the functions in the reference pages listed in the SEE ALSO section should be used for character classification.

#### RATIONALE

> None.

#### FUTURE DIRECTIONS

> None.

#### SEE ALSO

> isalnum, isalpha, iscntrl, isdigit, isgraph, islower, isprint, ispunct, isupper, isxdigit, setlocale, uselocale

> XBD Locale, <ctype.h>, <locale.h>

#### CHANGE HISTORY

> First released in Issue 1. Derived from Issue 1 of the SVID.

#### Issue 6

> The normative text is updated to avoid use of the term "must" for application requirements.

#### Issue 7

> The isspace_l() function is added from The Open Group Technical Standard, 2006, Extended API Set Part 4.

> POSIX.1-2008, Technical Corrigendum 1, XSH/TC1-2008/0303 [302], XSH/TC1-2008/0304 [283], and XSH/TC1-2008/0305 [283] are applied.

End of informative text.

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