Datasheet

The C and C++ Libraries

4.13 ISO implementation definition

This section describes how the libraries fulfill the requirements of the ANSI

specification.

4.13.1 ANSI C library implementation definition

The ANSI C library variants are listed in Library naming conventions on page 4-105.

The ANSI specification leaves some details to the implementors, but requires their

implementation choices to be documented. The implementation details are described in

this section.

• The macro

NULL

expands to the integer constant 0.

• If a program redefines a reserved external identifier, an error might occur when

the program is linked with the standard libraries. If it is not linked with standard

libraries, no error is diagnosed.

• The

assert()

function prints the following message and then calls the

abort()

function:

*** assertion failed: expression, file _FILE_, line _LINE_

The following functions test for character values in the range EOF (–1) to 255

(inclusive):

•

isalnum()

•

isalpha()

•

iscntrl()

•

islower()

•

isprint()

•

isupper()

•

ispunct().