---
name: "isspace"
section: "3"
platform: "macos"
package: "Libc"
version: "1752.120.2"
release: "macOS 26.5"
platforms: ["linux", "freebsd", "macos"]
url: "https://new.carta.tech/isspace"
---

# isspace(3)

white-space character test

## NAME

**isspace** – white-space character test

## LIBRARY

Standard C Library (libc, -lc)

## SYNOPSIS

**#include \<ctype.h\>**

*int*\

**isspace**(*int c*);

## DESCRIPTION

The **isspace**() function tests for the white-space characters. For any locale, this includes the following standard characters:

| |
| --- |
| \`\`\\t'' \`\`\\n'' \`\`\\v'' \`\`\\f'' \`\`\\r'' \`\` '' |

In the "C" locale, **isspace**() successful test is limited to these characters only. The value of the argument must be representable as an *unsigned char* or the value of EOF.

## RETURN VALUES

The **isspace**() function returns zero if the character tests false and returns non-zero if the character tests true.

## COMPATIBILITY

The 4.4BSD extension of accepting arguments outside of the range of the *unsigned char* type in locales with large character sets is considered obsolete and may not be supported in future releases. The **iswspace**() function should be used instead.

## SEE ALSO

[ctype(3)](/ctype/3.md), [isalnum\_l(3)](/isalnum_l/3.md), [iswspace(3)](/iswspace/3.md), [multibyte(3)](/multibyte/3.md), [ascii(7)](/ascii/7.md)

## STANDARDS

The **isspace**() function conforms to ISO/IEC 9899:1990 (“ISO C90”).