C/C++ Programmer's Guide (G06.27+, H06.08+, J06.03+)

For the descriptions of the pragmas supported by native C, see Chapter 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 more details on how to recognize the diagnostic that is printed by the assert() function and
information on the termination behavior of the assert() function, see the assert() function in the
Guardian Native C Library Calls Reference Manual.
These 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 (that is 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, see 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 the signals by the C runtime.
The default handling is reset if a SIGILL signal is received by a handler specified to the signal()
function.
Streams and Files
The last line of a text stream does not require a terminating newline character. The file is written
with the characters requested.
The space characters that are written out to a text stream immediately before a newline character
appear when the stream is read back in.
Zero null characters may be appended to data written to a binary stream.
The file position indicator of an append mode stream is initially positioned at the start of the file.
A write on a text stream does not cause the associated file to be truncated beyond that point.
Full buffering best describes the file buffering of the native C run-time.
A zero-length file can actually exist.
These are the rules for composing a valid file name:
• In the Guardian environment, the file name is formed as specified by the Guardian file-name
format, which is composed of system name, volume name, subvolume name and file name,
each separated by a period(.). Except for the file name, all the other fields can be omitted,
then the default subvolume is the present working subvolume.
• In the OSS environment, the newline file name must be a valid OSS filename.
Implementation-Defined Behavior of Native C 399