MPLAB C Compiler for PIC24 MCUs and dsPIC DSCs ... - Microchip

16-Bit C Compiler User’s Guide
A.16 LIBRARY FUNCTIONS
Implementation-Defined Behavior for Library Functions is covered in section G.3.14 of
the ANSI C Standard.
What is the null pointer constant to which the macro NULL expands? (ISO 7.1.5)
0.
How is the diagnostic printed by the assert function recognized, and what is the
termination behavior of this function? (ISO 7.2)
The assert function prints the file name, line number and test expression, separated by
the colon character (‘:’). It then calls the abort function.
What characters are tested for by the isalnum, isalpha, iscntrl, islower, isprint and
isupper functions? (ISO 7.3.1)
TABLE A-5: CHARACTERS TESTED BY IS FUNCTIONS
Function Characters tested
isalnum One of the letters or digits: isalpha or isdigit.
isalpha One of the letters: islower or isupper.
iscntrl One of the five standard motion control characters, backspace and alert:
\f, \n, \r, \t, \v, \b, \a.
islower One of the letters ‘a’ through ‘z’.
isprint A graphic character or the space character: isalnum or ispunct or
space.
isupper One of the letters ‘A’ through ‘Z’.
ispunct One of the characters: ! " # % & ' ( ) ; < = > ? [ \ ] * + , - . / : ^
What values are returned by the mathematics functions after a domain errors?
(ISO 7.5.1)
NaN.
Do the mathematics functions set the integer expression errno to the value of the
macro ERANGE on underflow range errors? (ISO 7.5.1)
Yes.
Do you get a domain error or is zero returned when the fmod function has a second
argument of zero? (ISO 7.5.6.4)
Domain error.
DS51284H-page 136 © 2008 Microchip Technology Inc.