Escape sequences

Escape sequences are used to represent certain special characters within string literals and character constants.

The following escape sequences are available. ISO C requires a diagnostic if the backslash is followed by any character not listed here:

Notes

Of the octal escape sequences, \0 is the most useful because it represents the terminating null character in null-terminated strings.

The new-line character \n has special meaning when used in text mode I/O: it is converted to the OS-specific newline byte or byte sequence.

Octal escape sequences have a length limit of three octal digits but terminate at the first character that is not a valid octal digit if encountered sooner.

Hexadecimal escape sequences have no length limit and terminate at the first character that is not a valid hexadecimal digit. If the value represented by a single hexadecimal escape sequence does not fit the range of values represented by the character type used in this string literal or character constant (char, char16_t, char32_t, or wchar_t), the result is unspecified.

A universal character name in a narrow string literal or a 16-bit string literal may map to more than one character, e.g. \U0001f34c is 4 char code units in UTF-8 (\xF0\x9F\x8D\x8C) and 2 char16_t code units in UTF-16 (\uD83C\uDF4C)).

The question mark escape sequence \? is used to prevent trigraphs from being interpreted inside string literals: a string such as "??/" is compiled as "\", but if the second question mark is escaped, as in "?\?/", it becomes "??/"

Example

#include <stdio.h>
 
int main(void)
{
    printf("This\nis\na\ntest\n\nShe said, \"How are you?\"\n");
}

This
is
a
test
 
She said, "How are you?"

References

• C11 standard (ISO/IEC 9899:2011):
• 5.2.2 Character display semantics (p: 24-25)
• 6.4.4.4 Character constants (p: 67-70)
• C99 standard (ISO/IEC 9899:1999):
• 5.2.2 Character display semantics (p: 19-20)
• 6.4.4.4 Character constants (p: 59-61)
• C89/C90 standard (ISO/IEC 9899:1990):
• 2.2.2 Character display semantics
• 3.1.3.4 Character constants

See also

• ASCII chart