C/C++ Programmer's Guide (G06.25+)

HP C Implementation-Defined Behavior
HP C/C++ Programmer’s Guide for NonStop Systems—429301-008
A-6
G.3.14 Library Functions
When an include file is specified as <filename>:
•
If the compiler is running in the Guardian environment, the only subvolume
searched is the compiler’s subvolume (usually, $system.system)
•
If the compiler is running in the OSS environment, the only directory searched is
/usr/include.
The SSV pragma can be used to modify the subvolume searched when running under
Guardian, and the -I option can be used to modify the search directories when
running under OSS.
For the descriptions of the pragmas supported by native C, see Section 13, Compiler
Pragmas.
When the date or time of translation is not available, the definitions of the __DATE__
and __TIME__ macros are January 1, 1970 and 00:00:00, respectively.
G.3.14 Library Functions
OL is the null pointer constant to which the macro NULL expands.
For information on how to recognize the diagnostic that is printed by the assert()
function and information on the termination behavior of the assert() function, refer to
the assert() function in the Guardian Native C Library Calls Reference Manual.
The following characters are tested for by the isalnum(), isalpha(), iscntrl(),
islower(), isprint(), and isupper() functions:
•
isalnum() returns true for characters a–z, A–Z, 0–9
•
isalpha() returns true for characters a–z, A–Z
•
iscntrl() returns true for values 0–31, 127
•
islower() returns true for characters a–z
•
isprint() returns true for values 32–126
•
isupper() returns true for characters A–Z
An undefined value is returned by the mathematics functions after a domain error, and
errno is set to EDOM.
The mathematics functions set the integer expression errno to the value of the macro
ERANGE on underflow range errors.
When the fmod() function has a second argument of zero, fmod() returns the value
of the first argument (i.e. zero is treated as one).
Signals
For the set of signals for the signal() function and a description of the parameters
and the usage of each signal, refer to the signal(4) reference page online or in the
Open System Services System Calls Reference Manual.
For each signal recognized by the signal() function, at program startup the handler
SIG_DFL is registered for the all of the signals by the C runtime.