HP C
Run-Time Library Reference Manual for
OpenVMS Systems
For OpenVMS Version 7.3-2 and higher, DECC$EXEC_FILEATTR_INHERITANCE
can be defined to 1 or 2, or be disabled:
- With DECC$EXEC_FILEATTR_INHERITANCE defined to 1, a child process
inherits file positioning for all file access modes except append.
- With DECC$EXEC_FILEATTR_INHERITANCE defined to 2, a child process
inherits file positioning for all file access modes including append.
- With DECC$EXEC_FILEATTR_INHERITANCE disabled, a child process does
not inherit the file position for any access modes.
DECC$FILENAME_UNIX_ONLY
With DECC$FILENAME_UNIX_ONLY enabled, file names are never interpreted
as OpenVMS style names. This prevents any interpretation of the
following as OpenVMS special characters:
DECC$FILENAME_UNIX_NO_VERSION
With DECC$FILENAME_UNIX_NO_VERSION enabled, OpenVMS version numbers are
not supported in UNIX style file names.
With DECC$FILENAME_UNIX_NO_VERSION disabled, in UNIX style names,
version numbers are reported preceded by a period (.).
DECC$FILENAME_UNIX_REPORT
With DECC$FILENAME_UNIX_REPORT enabled, all file names are reported in
UNIX style unless the caller specifically selects OpenVMS style. This
applies to
getpwnam
,
getpwuid
,
argv[0]
,
getname
,
fgetname
, and
tempnam
.
With DECC$FILENAME_UNIX_REPORT disabled, unless specified in the
function call, file names are reported in OpenVMS style.
DECC$FILE_PERMISSION_UNIX
With DECC$FILE_PERMISSION_UNIX enabled, the file permissions for new
files and directories are set according to the file creation mode and
umask
. This includes mode 0777. When an earlier version of the file exists,
the file permissions for the new file are inherited from the earlier
version. This mode sets DELETE permission for a new directory when
WRITE permission is enabled.
With DECC$FILE_PERMISSION_UNIX disabled, modes 0 and 0777 indicate
using RMS default protection or protection from the previous version of
the file. Permissions for new directories also follow OpenVMS rules,
including disabling DELETE permissions.
DECC$FILE_SHARING
With DECC$FILE_SHARING enabled, all files are opened with full sharing
enabled (FAB$M_DEL | FAB$M_GET | FAB$M_PUT | FAB$M_UPD). This is set as
a logical OR with any sharing mode specified by the caller.
DECC$FIXED_LENGTH_SEEK_TO_EOF
With DECC$FIXED_LENGTH_SEEK_TO_EOF enabled,
lseek
,
fseeko
, and
fseek
with the direction paremeter set to SEEK_END will position
relative to the last byte in the file for files with fixed-length
records.
With DECC$FIXED_LENGTH_SEEK_TO_EOF disabled,
lseek
,
fseek
, and
fseeko
when called with SEEK_EOF on files with fixed-length records, will
position relative to the end of the last record in the file.
DECC$GLOB_UNIX_STYLE
Enabling DECC$GLOB_UNIX_STYLE selects the UNIX mode of the
glob
function, which uses UNIX style filenames and wildcards instead of
OpenVMS style filenames and wildcards.
DECC$LOCALE_CACHE_SIZE
DECC$LOCALE_CACHE_SIZE defines how much memory, in bytes, to allocate
for caching locale data. The default value is 0, which disables the
locale cache.
Default: 0
Maximum: 2147483647
DECC$MAILBOX_CTX_STM
By default, an
open
on a local mailbox that is not a pipe treats mailbox records as having
a record attribute of FAB$M_CR.
With DECC$MAILBOX_CTX_STM enabled, the record attribute FAB$M_CR is not
set.
DECC$NO_ROOTED_SEARCH_LISTS
When the
decc$to_vms
function evaluates a UNIX style path string, if it determines the first
element to be a logical name, then:
- For rooted logicals or devices, it appends ":[000000]" to the
logical name.
For example, if
log1
is a rooted logical ($DEFINE LOG1 [DIR_NAME.]) then
/log1/filename.ext
translates to LOG1:[000000]FILENAME.EXT.
- For nonrooted logicals, it appends just a colon (:) to the logical
name.
For example, if
log2
is a nonrooted logical ($ DEFINE LOG2 [DIR_NAME]), then
/log2/filename.ext
translates to LOG2:FILENAME.EXT.
- If the first element is a search-list logical, the translation
proceeds by evaluating the first element in the search list, and
translating the path as previously described.
The preceding three cases lead to predictable, expected results.
In the case where the first element is a search list that consists of a
mixture of rooted and nonrooted logicals, translating paths as
described previously can lead to different behavior from that of older
versions of OpenVMS (before OpenVMS Version 7.3-1):
- Before OpenVMS Version 7.3-1, regardless of the contents of the
logical, the
decc$to_vms
function appended only a colon (:). For search lists that consisted of
a mixture of rooted and nonrooted logicals, this resulted in certain
expected behaviors.
- For OpenVMS Version 7.3-1 and later, if the first element of the
mixed search list is a rooted logical, then
decc$to_vms
appends ":[000000]" to the logical name, resulting in different
behavior from that of OpenVMS releases prior to Version 7.3-1.
DECC$NO_ROOTED_SEARCH_LISTS controls how the
decc$to_vms
function resolves search-list logicals and provides a means to restore
the OpenVMS behavior prior to Version 7.3-1.
With DECC$NO_ROOTED_SEARCH_LISTS enabled:
- If a logical is detected in a file specification, and it is a
search list, then a colon (:) is appended when forming the OpenVMS file
specification.
- If it is not a search list, the behavior is the same as with
DECC$NO_ROOTED_SEARCH_LISTS disabled.
Enabling this feature logical provides the pre-Version 7.3-1 behavior
for search list logicals.
With DECC$NO_ROOTED_SEARCH_LISTS disabled:
- If a logical is detected in a file specification, and it is a
rooted logical (or a search list whose first element is a rooted
logical), then ":[000000]" is appended when forming the OpenVMS file
specification.
- If it is a nonrooted logical (or a search list whose first element
is a nonrooted logical), then just a colon (:) is appended.
Disabling this feature logical provides the behavior for OpenVMS
Version 7.3-1 and later.
DECC$PIPE_BUFFER_QUOTA
OpenVMS Version 7.3-2 adds an optional fourth argument of type
int
to the
pipe
function to specify the buffer quota of the pipe's mailbox. In previous
OpenVMS versions, the buffer quota was equal to the buffer size.
DECC$PIPE_BUFFER_QUOTA lets you specify a buffer quota to use for the
pipe
function if the optional fourth argument of that function is omitted.
If the optional
pipe
fourth argument is omitted and DECC$PIPE_BUFFER_QUOTA is not defined,
then the buffer quota defaults to the buffer size, as before.
Default: 512
Minimum: 512
Maximum: 2147483647
DECC$PIPE_BUFFER_SIZE
The system default buffer size of 512 bytes for pipe write operations
can limit performance and generate extra line feeds when handling
messages longer than 512 bytes.
DECC$PIPE_BUFFER_SIZE allows a larger buffer size to be used for pipe
functions such as
pipe
and
popen
. A value of 512 to 65535 bytes can be specified.
If DECC$PIPE_BUFFER_SIZE is not specified, the default buffer size 512
is used.
Default: 512
Minimum: 512
Maximum: 65535
DECC$POPEN_NO_CRLF_REC_ATTR
With DECC$POPEN_NO_CRLF_REC_ATTR disabled, a pipe opened with the
popen
function has its record attributes set to CR/LF carriage control
(fab$b_rat |= FAB$M_CR). This is the default behavior.
With DECC$POPEN_NO_CRLF_REC_ATTR enabled, CR/LF carriage control is
prevented from being added to the pipe records. This is compatible with
UNIX behavior, but be aware that enabling this feature might result in
undesired behavior from other functions, such as
gets
, that rely on the carriage-return character.
DECC$POSIX_COMPLIANT_PATHNAMES
With DECC$POSIX_COMPLIANT_PATHNAMES enabled, an application is allowed
to present POSIX-compliant pathnames to any C RTL function that accepts
a pathname.
By default DECC$POSIX_COMPLIANT_PATHNAMES is disabled, and the usual C
RTL behavior prevails. This disabled mode includes interpretation of
pathnames as UNIX style specifications and uses rules that are
different and unrelated to POSIX-compliant pathname processing.
To enable DECC$POSIX_COMPLIANT_PATHNAMES, set it to one of the
following values:
|
1
|
All pathnames are designated as POSIX style.
|
|
2
|
Pathnames that end in "
:
" or contain any of the bracket characters "
[]<>
", and that can be successfully parsed by the SYS$FILESCAN service, are
designated as OpenVMS style. Otherwise, they are designated as POSIX
style.
|
|
3
|
The pathnames "
.
" and "
..
", or pathnames that contain "
/
" are designated as POSIX style. Otherwise, they are designated as
OpenVMS style.
|
|
4
|
All pathnames are designated as OpenVMS style.
|
See Section 12.3.1 for more information.
DECC$POSIX_SEEK_STREAM_FILE
With DECC$POSIX_SEEK_STREAM_FILE enabled, positioning beyond
end-of-file on STREAM files does not write to the file until the next
write. If the write is beyond the current end-of-file, this positions
beyond the old end-of-file, and the start position for the write is
filled with zeros.
With DECC$POSIX_SEEK_STREAM_FILE disabled, positioning beyond
end-of-file will immediately write zeros to the file from the current
end-of-file to the new position.
DECC$POSIX_STYLE_UID
With DECC$POSIX_STYLE_UID enabled, 32-bit UIDs and GIDs are interpreted
as POSIX style identifiers.
With this logical name disabled, UIDs and GIDs are derived from the
process UIC.
This feature is only available on OpenVMS systems providing POSIX style
UID and GID support.
DECC$READDIR_DROPDOTNOTYPE
With DECC$READDIR_DROPDOTNOTYPE enabled,
readdir
when reporting files in UNIX style only reports the trailing period (.)
for files with no file type when the file name contains a period.
With this logical name disabled, all files without a file type are
reported with a trailing period.
DECC$READDIR_KEEPDOTDIR
The default behavior when reporting files in UNIX style from
readdir
is to report directories without a file type.
With DECC$READDIR_KEEPDOTDIR enabled, directories are reported in UNIX
style with a file type of ".DIR".
DECC$RENAME_NO_INHERIT
DECC$RENAME_NO_INHERIT provides more UNIX compliant behavior in the
rename
function. With DECC$RENAME_NO_INHERIT enabled, the following behaviors
are enforced:
- If the old argument points to the pathname of a file that
is not a directory, the new argument will not point to the
pathname of a directory.
- The new argument cannot point to a directory that exists.
- If the old argument points to the pathname of a directory,
the new argument will not point to the pathname of a file that
is not a directory.
- The new name for the file does not inherit anything from the old
name. The new name must be specified completely. For example:
Renaming "A.A" to "B" yields "B"
With this logical name disabled, you get the expected OpenVMS behavior.
For example:
Renaming "A.A" to "B" yields "B.A"
DECC$RENAME_ALLOW_DIR
Enabling DECC$RENAME_ALLOW_DIR restores the prior OpenVMS behavior of
the
rename
function by allowing conversion to a directory specification when the
second argument is an ambiguous file specification passed as a logical
name. The ambiguity is whether the logical name is a UNIX or OpenVMS
file specification. Consider the following example with
DECC$RENAME_ALLOW_DIR enabled:
rename("file.ext", "logical_name") /* where logical_name = dev:[dir.subdir] */
/* and :[dir.subdir] exists. */
|
This results in:
This example renames a file from one directory into another directory,
which is the same behavior as in legacy versions of OpenVMS (versions
before 7.3-1). Also in this example, if
dev:[dir.subdir]
does not exist,
rename
returns an error.
Disabling DECC$RENAME_ALLOW_DIR provides a more UNIX compliant
conversion of the
"logical_name"
argument of
rename
. Consider the following example with DECC$RENAME_ALLOW_DIR disabled:
rename("file.ext", "logical_name") /* where logical_name = dev:[dir.subdir] */
|
This results in:
This example renames the file using the
subdir
part of the
"logical_name"
argument as the new file name because on UNIX systems, renaming a file
to a directory is not allowed. So
rename
internally converts the
"logical_name"
to a file name, and
dev:[dir]subdir
is the most reasonable conversion it can perform.
This new feature switch has a side effect of causing rename to a
directory to take precedence over rename to a file. Consider this
example:
rename ( "file1.ext", "dir2" ) /* dir2 is not a logical */
|
With DECC$RENAME_ALLOW_DIR disabled, this example results in
dir2.ext
, regardless of whether or not subdirectory
[.dir2]
exists.
With DECC$RENAME_ALLOW_DIR enabled, this example results in
dir2.ext
only if subdirectory
[.dir2]
does not exist. If subdirectory
[.dir2]
does exist, the result is
[.dir2]file1.ext
.
Note
If DECC$RENAME_NO_INHERIT is enabled, UNIX compliant behavior is
expected, so DECC$RENAME_ALLOW_DIR is ignored, and renaming a file to a
directory is not allowed.
|
DECC$SELECT_IGNORES_INVALID_FD
With DECC$SELECT_IGNORES_INVALID_FD enabled,
select
fails with
errno
set to EBADF when an invalid file descriptor is specified in one of the
descriptor sets.
With DECC$SELECT_IGNORES_INVALID_FD disabled,
select
ignores invalid file descriptors.
DECC$STDIO_CTX_EOL
With DECC$STDIO_CTX_EOL enabled, writing to
stdout
and
stderr
for stream access is deferred until a terminator is seen or the buffer
is full.
With DECC$STDIO_CTX_EOL disabled, each
fwrite
generates a separate write, which for mailbox and record files
generates a separate record.
DECC$STREAM_PIPE
With DECC$STREAM_PIPE enabled, the C RTL
pipe
function uses the more UNIX compatible stream I/O.
With DECC$STREAM_PIPE disabled,
pipe
uses the OpenVMS legacy record I/O. This is the default.
DECC$STRTOL_ERANGE
With DECC$STRTOL_ERANGE enabled, the
strtol
behavior for an ERANGE error is corrected to consume all remaining
digits in the string.
With DECC$STRTOL_ERANGE disabled, the legacy behavior of leaving the
pointer at the failing digit is preserved.
DECC$THREAD_DATA_AST_SAFE
The C RTL has a mode that allocates storage for thread-specific data
allocated by threads at non-AST level separate for data allocated for
ASTs. In this mode, each access to thread-specific data requires a call
to LIB$AST_IN_PROG, which can add significant overhead when accessing
thread-specific data in the C RTL.
The alternate mode protects thread-specific data only if another
function has it locked. This protects data that is in use within the C
RTL, but does not protect the caller from an AST changing the data
pointed to.
This latter mode is now the C RTL default for the
strtok
,
ecvt
, and
fcvt
functions.
You can select the legacy AST safe mode by enabling
DECC$THREAD_DATA_AST_SAFE.
DECC$TZ_CACHE_SIZE
DECC$TZ_CACHE_SIZE specifies the number of time zones that can be held
in memory.
Default: 2
Maximum: 2147483647
DECC$UMASK
DECC$UMASK specifies the default value for the permission mask
umask
. By default, a parent C program sets the
umask
from the RMS default permissions for the process. A child process
inherits the parent's value for
umask
.
To enter the value as an octal value, add the leading zero; otherwise,
it is translated as a decimal value. For example:
Maximum: 0777
DECC$UNIX_LEVEL
With the DECC$UNIX_LEVEL logical name, you can manage multiple C RTL
feature logical names at once. By setting a value for DECC$UNIX_LEVEL
from 1 to 100, you determine the default value for groups of feature
logical names. The value you set has a cumulative effect: the higher
the value, the more groups that are affected. Setting a value of 20,
for example, enables all the feature logicals associated with a
DECC$UNIX_LEVEL of 20, 10, and 1.
The principal logical names affecting UNIX like behavior are grouped as
follows:
1 General corrections
10 Enhancements
20 UNIX style file names
30 UNIX style file attributes
90 Full UNIX behavior - No concessions to OpenVMS
Level 30 is appropriate for UNIX like programs such as BASH and GNV.
The DECC$UNIX_LEVEL values and associated groups of affected feature
logical names are:
General Corrections (DECC$UNIX_LEVEL 1)
DECC$FIXED_LENGTH_SEEK_TO_EOF 1
DECC$POSIX_SEEK_STREAM_FILE 1
DECC$SELECT_IGNORES_INVALID_FD 1
DECC$STRTOL_ERANGE 1
DECC$VALIDATE_SIGNAL_IN_KILL 1
General Enhancements (DECC$UNIX_LEVEL 10)
DECC$ARGV_PARSE_STYLE 1
DECC$EFS_CASE_PRESERVE 1
DECC$STDIO_CTX_EOL 1
DECC$PIPE_BUFFER_SIZE 4096
DECC$USE_RAB64 1
UNIX style file names (DECC$UNIX_LEVEL 20)
DECC$DISABLE_TO_VMS_LOGNAME_TRANSLATION 1
DECC$EFS_CHARSET 1
DECC$FILENAME_UNIX_NO_VERSION 1
DECC$FILENAME_UNIX_REPORT 1
DECC$READDIR_DROPDOTNOTYPE 1
DECC$RENAME_NO_INHERIT 1
DECC$GLOB_UNIX_STYLE
UNIX like file attributes (DECC$UNIX_LEVEL 30)
DECC$EFS_FILE_TIMESTAMPS 1
DECC$EXEC_FILEATTR_INHERITANCE 1
DECC$FILE_OWNER_UNIX 1
DECC$FILE_PERMISSION_UNIX 1
DECC$FILE_SHARING 1
UNIX compliant behavior (DECC$UNIX_LEVEL 90)
DECC$FILENAME_UNIX_ONLY 1
DECC$POSIX_STYLE_UID 1
DECC$USE_JPI$_CREATOR 1
DECC$DETACHED_CHILD_PROCESS 1
|
Notes
- Defining a logical name for an individual feature logical
supersedes the default value established by DECC$UNIX_LEVEL for that
feature.
- Future revisions of the C RTL may add new feature logicals to a
given DECC$UNIX_LEVEL. For applications that specify that UNIX level,
the effect is to enable those new feature logicals by default.
|
DECC$UNIX_PATH_BEFORE_LOGNAME
With DECC$UNIX_PATH_BEFORE_LOGNAME enabled, when translating a UNIX
file name not starting with a leading slash (/), an attempt is made to
match this to a file or directory in the current directory. If this is
not found and the name is valid as a logical name in an OpenVMS file
name, an attempt is made to translate the logical name and, if found,
is used as part of the resulting file name.
Enabling DECC$UNIX_PATH_BEFORE_LOGNAME overrides the setting for
DECC$DISABLE_TO_VMS_LOGNAME_TRANSLATION.
DECC$USE_JPI$_CREATOR
When enabled, DECC$USE_JPI$_CREATOR determines the parent process ID in
getppid
by calling $GETJPI using item JPI$_CREATOR instead of JPI$_OWNER.
This feature is only available on systems supporting POSIX style
session identifiers.
DECC$USE_RAB64
With DECC$USE_RAB64 enabled, open functions allocate a RAB64 structure
instead of the traditional RAB structure.
This provides latent support for file buffers in 64-bit memory.
DECC$VALIDATE_SIGNAL_IN_KILL
With DECC$VALIDATE_SIGNAL_IN_KILL enabled, a signal value that is in
the range 0 to _SIG_MAX but is not supported by the C RTL generates an
error with
errno
set to EINVAL, which makes the behavior the same as for
raise
.
With this logical name disabled, validation of signals is restricted to
checking that the signal value is in the range 0 to _SIG_MAX. If
sys$sigprc
fails,
errno
is set based on
sys$sigprc
exit status.
DECC$V62_RECORD_GENERATION
OpenVMS Versions 6.2 and higher can output record files using different
rules.
With DECC$V62_RECORD_GENERATION enabled, the output mechanism follows
the rules used for OpenVMS Version 6.2.
DECC$WRITE_SHORT_RECORDS
The DECC$WRITE_SHORT_RECORDS feature logical supports a previous change
to the
fwrite
function (to accommodate writing records with size less than the
maximum record size), while retaining the legacy way of writing records
to a fixed-length file as the default behavior:
With DECC$WRITE_SHORT_RECORDS enabled, short-sized records (records
with size less than the maximum record size) written at EOF are padded
with zeros to align records on record boundaries. This is the behavior
seen in OpenVMS Version 7.3-1 and some ACRTL ECOs of that time period.
With DECC$WRITE_SHORT_RECORDS disabled, the legacy behavior of writing
records with no padding is implemented. This is the recommended and
default behavior.
DECC$XPG4_STRPTIME
XPG5 support for
strptime
introduces pivoting year support so that years in the range 0 to 68 are
in the 21st century, and years in the range 69-99 are in the 20th
century.
With DECC$XPG4_STRPTIME enabled, XPG5 support for the pivoting year is
disabled and all years in the range 0 to 99 are in the current century.