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

If a file with a new name already exists prior to a call to the rename() function, it returns a
nonzero value without renaming the file.
The output for %p conversion in the fprintf() function formats the value of a pointer to a void
argument using the format specified by the x conversion code.
The input for %p conversion in the fscanf() function matches an unsigned hexadecimal integer that
uses the lowercase letters a through f to represent the digits 10 through 15. The corresponding
obj_ptr must be a pointer to void. Consequently, the integer is interpreted as a pointer to void.
The hyphen character (-) is treated as just another character in the scan list if it is not the first or
the last character in the scan list.
tmpfile()
An open temporary file is removed if the program terminates abnormally.
errno
The macro errno is set to 4009 by the fgetpos() or ftell() function on failure.
A call to the perror() function prints the textual error message corresponding to the value of the
errno, optionally preceded by a specified string.
Memory
The behavior of the calloc(), malloc(), or realloc() function if the size requested is zero
is:
• In the Guardian environment, calloc(), malloc(), and realloc() abort with runtime
error 40.
• In the OSS environment on NonStop S-series systems, calloc(), malloc(), and realloc()
return a non-NULL pointer. These pointers should not be dereferenced.
abort()
When the abort() function is called, all open and temporary files are closed. The temporary files
are deleted.
exit()
The status returned by the exit() function if the value of the argument is other than zero,
EXIT_SUCCESS, or EXIT_FAILURE is:
If the value is negative, the exit() function will return EXIT_FAILURE.
If the value is positive, the exit condition code is equal to status. See the Guardian Procedure Calls
Reference Manual.
getenv()
The environment names are always in uppercase. These four run-time parameters are always
present:
DescriptionParameter
Gives the name of the standard input file, stdin.STDIN
Gives the name of the standard output file, stdout.STDOUT
Gives the name of the standard error file, stderr.STDERR
Gives the default volume and subvolume names used to qualify partial file names.DEFAULTS
To alter the environment list obtained by a call to the getenv() function, use the PARAM command,
the syntax for which is:
412 HP C Implementation-Defined Behavior