TOLOWER(P) POSIX Programmer's Manual TOLOWER(P)
tolower - transliterate uppercase characters to lowercase
int tolower(int c);
The tolower() function has as a domain a type int, the value of which is representable as
an unsigned char or the value of EOF. If the argument has any other value, the behavior is
undefined. If the argument of tolower() represents an uppercase letter, and there exists a
corresponding lowercase letter (as defined by character type information in the program
locale category LC_CTYPE ), the result shall be the corresponding lowercase letter. All
other arguments in the domain are returned unchanged.
Upon successful completion, tolower() shall return the lowercase letter corresponding to
the argument passed; otherwise, it shall return the argument unchanged.
No errors are defined.
The following sections are informative.
setlocale() , the Base Definitions volume of IEEE Std 1003.1-2001, Chapter 7, Locale,
Portions of this text are reprinted and reproduced in electronic form from IEEE Std
1003.1, 2003 Edition, Standard for Information Technology -- Portable Operating System
Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by
the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the
event of any discrepancy between this version and the original IEEE and The Open Group
Standard, the original IEEE and The Open Group Standard is the referee document. The orig-
inal Standard can be obtained online at http://www.opengroup.org/unix/online.html .
IEEE/The Open Group 2003 TOLOWER(P)