CrossWorks for ARM User Guide

Descriptiontolower converts an uppercase letter to a corresponding lowercase letter.If the argument c is a character for which isupper is true, tolower returns thecorresponding lowercase letter; otherwise, the argument is returned unchanged.Portabilitytolower conforms to ISO/IEC 9899:1990 (C90) and ISO/IEC 9899:1999 (C99).toupperSynopsisDescription#include int toupper(int c);toupper converts a lowercase letter to a corresponding uppercase letter.If the argument c is a character for which islower is true, toupper returns thecorresponding uppercase letter; otherwise, the argument is returned unchanged.Portabilitytoupper conforms to ISO/IEC 9899:1990 (C90) and ISO/IEC 9899:1999 (C99). - ErrorsThe header file defines macros defines several macros, all relating to thereporting of error conditions.MacroserrnoError numbererrnoSynopsisDescription#include int errno;errno expands to a modifiable lvalue of type int, the value of which is set to a positiveerror number by several library functions.The ISO standard does not specify whether errno is a macro or an identifier declaredwith external linkage. Portable programs must not make assumptions about theimplementation of errno.The value of errno is zero at program startup, but is never set to zero by any libraryfunction. The value of errno may be set to a nonzero value by a library function, andthis effect is documented in each functio that does so.Chapter 28 - Errors247