Index for Section 3

Alphabetical listing for C

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conv(3)
NAME
  toascii, tolower, _tolower, toupper, _toupper - Translate characters

SYNOPSIS
  #include <ctype.h>

  int toascii(
	  int c );

  int tolower(
	  int c );

  int _tolower(
	  int c );

  int toupper(
	  int c );

  int _toupper(
	  int c );

LIBRARY
  Standard C Library (libc)

STANDARDS
  Interfaces documented on this reference page conform to industry standards
  as follows:

  toascii(), tolower(), _tolower(), toupper(), _toupper():  XPG4, XPG4-UNIX

  Refer to the standards(5) reference page for more information about
  industry standards and associated tags.

PARAMETERS
  c   Specifies the character to be converted.

DESCRIPTION
  The toascii(), tolower(), _tolower(), toupper(), and _toupper() functions
  translate all characters, including multibyte characters, to their
  specified character values.

  The toascii() function converts its input to a 7-bit ASCII character.

  The tolower() function takes an int value that can be represented as an
  unsigned char or the value of EOF (defined in the stdio.h header file) as
  its input.

  When the input of the tolower() function expresses an uppercase letter, and
  there exists a corresponding lowercase letter (as defined by character type
  information in the program locale category LC_CTYPE), the corresponding
  lowercase letter is returned. All other input values in the domain are
  returned unchanged. The tolower() function has as its domain the range -1
  through 255.

  In the C locale, or in a locale where case-conversion information is not
  defined, the tolower() function determines the case of characters according
  to the rules of the Portable Character Set (ASCII characters). Characters
  outside the ASCII range of characters are returned unchanged.

  The _tolower() macro is equivalent to the tolower() function, but executes
  faster. If the value of the c parameter to the _tolower() macro does not
  have a corresponding lowercase character, the results of the function are
  undefined.

  The toupper() function takes an int value that can be represented as an
  unsigned char or the value of EOF (defined in the stdio.h header file) as
  its input.

  When the input of the toupper() function expresses a lowercase letter, and
  there exists a corresponding uppercase letter (as defined by character type
  information in the program locale category LC_CTYPE), the corresponding
  uppercase letter is returned. All other input values in the domain are
  returned unchanged. The toupper() function has as its domain the range -1
  through 255.

  In the C locale, or in a locale where case-conversion information is not
  defined, the toupper() function determines the case of characters according
  to the rules of the Portable Character Set (ASCII characters). Characters
  outside the ASCII range of characters are returned unchanged.

  The _toupper() macro is equivalent to the toupper() function, but executes
  faster. If the value of the c parameter to the _toupper() macro does not
  have a corresponding uppercase character, the results of the function are
  undefined.

NOTES
  The LC_CTYPE category of the current locale affects all conversions. See
  the i18n_intro(5) reference page for more information on locale variables.

RETURN VALUES
  The toascii() function returns the logical AND of parameter c and the value
  0X7F.

  When the c parameter is a character for which the isupper() function is
  TRUE, there is a corresponding character for which the islower() function
  is also TRUE.	 That lowercase character is returned by the tolower()
  function or by the _tolower() macro. Otherwise, the c parameter is returned
  unchanged.

  When the c parameter is a character for which the islower() function is
  TRUE, there is a corresponding character for which the isupper() function
  is also TRUE.	 That uppercase character is returned by the toupper()
  function or by the _toupper() macro. Otherwise, the c parameter is returned
  unchanged.

SEE ALSO
  Functions: ctype(3)

  Other: i18n_intro(5), standards(5)

Index for Section 3

Alphabetical listing for C

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