Another small step in my side project of documenting all OpenMP routines in libgomp.texi Here, only 'omp_display_env' is added. (New since OpenMP 5.1 but since a long time in GCC, some fineprint in both the implementation and in the documentation is based on TR11.)
* * * RFC - regarding printing the values (env.c not the documentation): I am wondering whether to change "OMP_VAR = 'val'" to "OMP_VAR='val'", i.e. to remove the spaces around the equal sign. Pro: The latter is friendlier when using the env var with POSIX shells / Bash as those do not permit spaces. (While 'setenv' in the cshell requires a space instead of an equal size.) Since OpenMP has the '[device] ' prevfix which is used by many implementations, including GCC, copy'n'paste is now harder and the benefit of removing the space is lower. Additionally, the OpenMP document has "format NAME ’=’ VALUE" which also implies no spaces and LLVM's runtime library also prints it without spaces. Thoughts? (The attached patch documents the current implementation.) * * * Comments or suggestions to the .texi patch itself? Tobias ----------------- Siemens Electronic Design Automation GmbH; Anschrift: Arnulfstraße 201, 80634 München; Gesellschaft mit beschränkter Haftung; Geschäftsführer: Thomas Heurung, Frank Thürauf; Sitz der Gesellschaft: München; Registergericht München, HRB 106955
libgomp.texi: Document omp_display_env libgomp/ChangeLog: * libgomp.texi (Environment Display Routine): Uncomment and add omp_display_env description. (OMP_DISPLAY_ENV): Update wording, add 'see also'. libgomp/libgomp.texi | 109 ++++++++++++++++++++++++++++++++++++++++++++------- 1 file changed, 94 insertions(+), 15 deletions(-) diff --git a/libgomp/libgomp.texi b/libgomp/libgomp.texi index c727850397d..9999686f712 100644 --- a/libgomp/libgomp.texi +++ b/libgomp/libgomp.texi @@ -570,7 +570,7 @@ specification in version 5.2. @c * Interoperability Routines:: * Memory Management Routines:: @c * Tool Control Routine:: -@c * Environment Display Routine:: +* Environment Display Routine:: @end menu @@ -2919,18 +2919,93 @@ was already deallocated or when the used allocator has already been destroyed. @c @node Tool Control Routine +@c @section Tool Control Routine @c @c FIXME -@c @node Environment Display Routine -@c @section Environment Display Routine -@c -@c Routine to display the OpenMP number and the initial value of ICVs. -@c It has C linkage and do not throw exceptions. -@c -@c menu -@c * omp_display_env:: <fixme> -@c end menu +@node Environment Display Routine +@section Environment Display Routine + +Routine to display the OpenMP number and the initial value of ICVs. +It has C linkage and do not throw exceptions. + +@menu +* omp_display_env:: print the initial ICV values +@end menu + +@node omp_display_env +@subsection @code{omp_display_env} -- print the initial ICV values +@table @asis +@item @emph{Description}: +Each time this routine is invoked, the GCC version number and initial value of +internal control variables (ICVs) is shown on @code{stderr}. Initial value +denotes the value at startup after evaluating the environment variables, such +that later calls to API routines or clauses used in enclosing constructs do not +affect the @emph{displayed} values. + +If the @var{verbose} argument is @code{false}, only the OpenMP version and +standard OpenMP ICVs are shown; if it is @code{true}, additionally, the +GCC-specific ICVs are shown. + +The output consists of multiple lines and starts with +@samp{OPENMP DISPLAY ENVIRONMENT BEGIN} followed by the name-value lines and +ends with @samp{OPENMP DISPLAY ENVIRONMENT END}. The name-value lines are +(usually and in GCC) indented by two spaces; the @var{name} is followed by an +equal sign and the @var{value} is enclosed in single quotes; in GCC, the equal +sign is preceded and followed by a single space. + +The first line has as @var{name} either (usually and in GCC) @samp{_OPENMP} or +@samp{openmp_version} and shows as value the OpenMP version number +(4-digit year, 2-digit month) of the implementation, matching the value of +the @code{_OPENMP} macro and, in Fortran, the named constant +@code{openmp_version}. + +In each of the succeeding lines, the @var{name} matches the environment-variable +name of an ICV and shows its value. Those line are optionally (and in GCC +always) prefixed by pair of brackets and a space, where the brackets enclose a +comma-separated list of devices to which the ICV-value combination +applies to; the value can either be a numeric device number or an abstract name +denoting all devices (@code{all}), the initial host device (@code{host}) or all +devices but the host (@code{device}). Note that the same ICV might be printed +multiple times for multiple devices, even if all have the same value. + +The effect when invoked from within a @code{target} region is unspecified. + +@item @emph{C/C++}: +@multitable @columnfractions .20 .80 +@item @emph{Prototype}: @tab @code{void omp_display_env(int verbose)} +@end multitable + +@item @emph{Fortran}: +@multitable @columnfractions .20 .80 +@item @emph{Interface}: @tab @code{subroutine omp_display_env(vebose)} +@item @tab @code{logical, intent(in) :: verbose} +@end multitable + +@item @emph{Example}: +Note that the GCC-specific ICVs, such as the shown @code{GOMP_SPINCOUNT}, +are only printed when @var{varbose} set to @code{true}. + +@smallexample +OPENMP DISPLAY ENVIRONMENT BEGIN + _OPENMP = '201511' + [host] OMP_DYNAMIC = 'FALSE' + [host] OMP_NESTED = 'FALSE' + [all] OMP_CANCELLATION = 'FALSE' + ... + [host] GOMP_SPINCOUNT = '300000' +OPENMP DISPLAY ENVIRONMENT END +@end smallexample + + +@item @emph{See also}: +@ref{OMP_DISPLAY_ENV}, @ref{Environment Variables}, +@ref{Implementation-defined ICV Initialization} + +@item @emph{Reference}: +@uref{https://www.openmp.org, OpenMP specification v5.1}, Section 3.15 +@end table + @c --------------------------------------------------------------------- @c OpenMP Environment Variables @@ -3182,12 +3257,16 @@ any change occurs. @item @emph{ICV:} none @item @emph{Scope:} not applicable @item @emph{Description}: -If set to @code{TRUE}, the OpenMP version number and the values -associated with the OpenMP environment variables are printed to @code{stderr}. -If set to @code{VERBOSE}, it additionally shows the value of the environment -variables which are GNU extensions. If undefined or set to @code{FALSE}, -this information is not shown. +If set to @code{TRUE}, the runtime displays the same information to +@code{stderr} as shown by the @code{omp_display_env} routine invoked with +@var{verbose} argument set to @code{false}. If set to @code{VERBOSE}, the same +information is shown as invoking the routine with @var{verbose} set to +@code{true}. If unset or set to @code{FALSE}, this information is not shown. +The result for any other value is unspecified; GCC shows an error and continues +the execution. +@item @emph{See also}: +@ref{omp_display_env} @item @emph{Reference}: @uref{https://www.openmp.org, OpenMP specification v4.5}, Section 4.12