External variables

The POSIX 1003.1 and X/Open CAE Specification 4.2 (XPG4.2) require that the C system header files define certain external variables. Additional variables are defined for use with POSIX or XPG4.2 functions. If you define one of the POSIX or XPG4 feature test macros and include one of these headers, the external variables will be defined in your program. These external variables are treated differently compared with other global variables in a multithreaded environment (values are thread-specific) and across a call to a fetched module (values are propagated).

To access the global variable values the following must be specified during C/C++ compiles and z/OS® bind:

Non-XPLINK (non-thread-safe)

C code must be compiled with the RENT or DLL option (C++ code needs no additional options). The SCEEOBJ autocall library must be specified during the bind.

Non-XPLINK (thread-safe)

No additional options are required for either C or C++. The _SHARE_EXT_VARS feature test macro, or the necessary _SHR_ prefixed feature test macros must be used.

Equivalently, the necessary thread-specific functions can be called directly (as documented below under each external variable).

XPLINK (non-thread-safe)

No additional options (besides XPLINK) are required for either C or C++. The C runtime library side-deck, member CELHS003 of the SCEELIB data set, must be included during the bind. (c89/cc/c++ automatically include this side-deck when the XPLINK link edit option (for example, c89 -Wl,XPLINK ...) is used.)

XPLINK (thread-safe)

No additional options (besides XPLINK) are required for either C or C++. The C runtime library side-deck, member CELHS003 of the SCEELIB dataset, must be included during the bind.

The _SHARE_EXT_VARS feature test macro, or the necessary _SHR_ prefixed feature test macros must be used. Equivalently, the necessary thread-specific functions can be called directly (as documented in the topics under each external variable).

LP64 (non-thread-safe)

No additional options (besides LP64 ) are required for either C or C++. The C runtime library side-deck, member CELQS003 of the SCEELIB dataset, must be included during the bind.

The _SHARE_EXT_VARS feature test macro, or the necessary _SHR_ prefixed feature test macros must be used.

Equivalently, the necessary thread-specific functions can be called directly (as documented in the topics under each external variable).

LP64 (thread-safe)

No additional options (besides LP64 ) are required for either C or C++. The C runtime library side-deck, member CELQS003 of the SCEELIB dataset, must be included during the bind. (c89/cc/c++ automatically include this side-deck when the LP64 link edit option (for example, c89 -Wl, LP64 ...) is used.)

The _SHARE_EXT_VARS feature test macro, or the necessary _SHR_ prefixed feature test macros must be used.

Equivalently, the necessary thread-specific functions can be called directly (as documented in the topics under each external variable).

errno

When a runtime library function fails, the function may do any of the following to identify the error:

Set errno to a documented value.
Set errno to a value that is not documented. You can use strerror() or perror() to get the message associated with the errno.
Not set errno.
Clear errno.

daylight

Daylight savings time flag set by tzset(). Note that other time zone sensitive functions such as ctime(), localtime(), mktime(), and strftime() implicitly call tzset().

Note: Use the __dlght() function to access the thread-specific value of daylight.

getdate_err

The variable is set to the value below when an error occurs in the getdate() function.

The DATEMSK environment variable is NULL or undefined.
The template file cannot be opened for reading.
Failed to get file status information.
The template file is not a regular file.
An error was encountered while reading the template file.
Memory allocation failed (not enough memory available).
No line in the template file matches the input specification.
Non-valid input specification. For example, February 31; or a time that can not be represented in a time_t (representing the time is seconds since Epoch - midnight, January 1, 1970 (UTC)).
Unable to determine current time.

Any changes to errno are unspecified.

Note: This value is unique for z/OS UNIX.

The getdate64() interface affects the same pointer to the thread-specific value of getdate_err and uses the same getdate_err values as the getdate() interface.

Note: Use the__gderr() function to access the thread-specific value of getdate_err. The getdate64() function affects the same pointer to the thread-specific value of getdate_err as the getdate() function does.

h_errno

An integer which holds the specific error code when the network name server encounters an error. The network name server is used by the gethostbyname() and gethostbyaddr() functions.

Note: Use the__h_errno() function to access the thread-specific value of h_errno. See also netdb.h.

Note: This variable is kept for historical reasons. However, it is used only in connection with the functions gethostbyaddr() and gethostbyname(), which are obsolescent in Single UNIX Specification, Version 3, so that the h_errno variable may also be withdrawn in the future.

__loc1

Restriction: This external variable is not supported in AMODE 64

A global character pointer which is set by the regex() function to point to the first matched character in the input string. Use the ____loc1() function to access the thread-specific value of __loc1.

Note:

This variable is kept for historical reasons. It was part of the Legacy Feature in Single UNIX Specification, Version 2, but has been withdrawn and is not supported as part of Single UNIX Specification, Version 3. New applications should use the interfaces supported by the <regex.h> header, which provide full internationalized regular expression functionality compatible with IEEE Std 1003.1-2001 Regular Expressions.

If it is necessary to continue using this symbol in an application written for Single UNIX Specification, Version 3, define the feature test macro _UNIX03_WITHDRAWN before including any standard system headers. The macro exposes all interfaces and symbols removed in Single UNIX Specification, Version 3. See also libgen.h.

loc1

Restriction: This external variable is not supported in AMODE 64.

A pointer to characters matched by regular expressions used by step(). The value is not propagated across a call to a fetched module.

Note:

loc2

Restriction: This external variable is not supported in AMODE 64

A pointer to characters matched by regular expressions used by step(). The value is not propagated across a call to a fetched module.

Note:

locs

Restriction: This external variable is not supported in AMODE 64

Used by advance() to stop regular expression matching in a string. The value is not propagated across a call to a fetched module. See also regexp.h.

Note:

optarg

Character pointer used by getopt() for options parsing variables.

Note: Use the__opargf() function to access the thread-specific value of optarg.

Note: This variable has been removed from stdio.h by Single UNIX Specification, Version 3 and is exposed for Version 3 only in unistd.h . See also stdio.h and unistd.h.

opterr

Error value used by getopt().

Note: Use the __operrf() function to access the thread-specific value of opterr.

Note: This variable has been removed from stdio.h by Single UNIX Specification, Version 3 and is exposed for Version 3 only in unistd.h. See also stdio.h and unistd.h.

optind

Integer pointer used by getopt() for options parsing variables.

Note: Use the__opindf() function to access the thread-specific value of optind.

Note: This variable has been removed from stdio.h by Single UNIX Specification, Version 3 and is exposed for Version 3 only in unistd.h. See also stdio.h and unistd.h.

optopt

Integer pointer used by getopt() for options parsing variables.

Note: Use the__opoptf() function to access the thread-specific value of optopt.

Note: This variable has been removed from stdio.h by Single UNIX Specification, Version 3 and is exposed for Version 3 only in unistd.h. See also stdio.h and unistd.h.

signgam

Storage for sign of lgamma(). This function defaults to thread-specific. See also math.h.

stderr

Standard Error stream. The external variable will be initialized to point to the enclave-level stream pointer for the standard error file. There is no multithreaded function. See also stdio.h.

stdin

Standard Input stream. The external variable will be initialized to point to the enclave-level stream pointer for the standard input file. There is no multithreaded function. See also stdio.h.

stdout

Standard Output stream. The external variable will be initialized to point to the enclave-level stream pointer for the standard output file. There is no multithreaded function. See also stdio.h.

t_errno

An integer which holds the specific error code when a failure occurs in one of the X/Open Transport Interface (XTI) functions. Use the __t_errno() function to access the thread-specific value of t_errno.

Note: Use the__t_errno() function to access the thread-specific value of t_errno.

timezone

Long integer difference from UTC and standard time as set by tzset(). Note that other time zone sensitive functions such as ctime(), localtime(), mktime(), and strftime() implicitly call tzset().

Note: Use the __tzone() function to access the thread-specific value of timezone.

tzname

Character pointer to unsized array of timezone strings used by tzset() and ctime(). The *tzname variable contains the Standard and Daylight Savings time zone names. If the TZ environment variable is present and correct, tzname will be set from TZ. Otherwise tzname will be set from the LC_TOD locale category. See the tzset() function for a description. There is no multithreaded function. See also time.h.