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18.14  Tool Control Routine

Summary

The omp_control_tool routine enables a program to pass commands to an active tool.

Format

 
int omp_control_tool(int command, int modifier, void *arg);  
 
integer function omp_control_tool(commandmodifier
integer (kind=omp_control_tool_kind) command 
integer modifier  

Constraints on Arguments

The following enumeration type defines four standard commands. 18.3 describes the actions that these commands request from a tool.

 
typedef enum omp_control_tool_t { 
  omp_control_tool_start = 1, 
  omp_control_tool_pause = 2, 
  omp_control_tool_flush = 3, 
  omp_control_tool_end = 4 
} omp_control_tool_t;  
 
integer (kind=omp_control_tool_kind), & 
          parameter :: omp_control_tool_start = 1 
integer (kind=omp_control_tool_kind), & 
          parameter :: omp_control_tool_pause = 2 
integer (kind=omp_control_tool_kind), & 
          parameter :: omp_control_tool_flush = 3 
integer (kind=omp_control_tool_kind), & 
          parameter :: omp_control_tool_end = 4  

Tool-specific values for command must be greater or equal to 64. Tools must ignore command values that they are not explicitly designed to handle. Other values accepted by a tool for command, and any values for modifier and arg are tool-defined.

tableStandard Tool Control Commands

TABLE 18.3: Standard Tool Control Commands
Command Action
omp_control_tool_start Start or restart monitoring if it is off. If monitoring is already on, this command is idempotent. If monitoring has already been turned off permanently, this command will have no effect.
omp_control_tool_pause Temporarily turn monitoring off. If monitoring is already off, it is idempotent.
omp_control_tool_flush Flush any data buffered by a tool. This command may be applied whether monitoring is on or off.
omp_control_tool_end Turn monitoring off permanently; the tool finalizes itself and flushes all output.

Binding

The binding task set for an omp_control_tool region is the generating task.

Effect

An OpenMP program may use omp_control_tool to pass commands to a tool. An application can use omp_control_tool to request that a tool starts or restarts data collection when a code region of interest is encountered, that a tool pauses data collection when leaving the region of interest, that a tool flushes any data that it has collected so far, or that a tool ends data collection. Additionally, omp_control_tool can be used to pass tool-specific commands to a particular tool. The following types correspond to return values from omp_control_tool:

 
typedef enum omp_control_tool_result_t { 
  omp_control_tool_notool = -2, 
  omp_control_tool_nocallback = -1, 
  omp_control_tool_success = 0, 
  omp_control_tool_ignored = 1 
} omp_control_tool_result_t;  
 
integer (kind=omp_control_tool_result_kind), & 
        parameter :: omp_control_tool_notool = -2 
integer (kind=omp_control_tool_result_kind), & 
        parameter :: omp_control_tool_nocallback = -1 
integer (kind=omp_control_tool_result_kind), & 
        parameter :: omp_control_tool_success = 0 
integer (kind=omp_control_tool_result_kind), & 
        parameter :: omp_control_tool_ignored = 1  

If the OMPT interface state is inactive, the OpenMP implementation returns omp_control_tool_notool. If the OMPT interface state is active, but no callback is registered for the tool-control event, the OpenMP implementation returns omp_control_tool_nocallback. An OpenMP implementation may return other implementation-defined negative values strictly smaller than -64; an application may assume that any negative return value indicates that a tool has not received the command. A return value of omp_control_tool_success indicates that the tool has performed the specified command. A return value of omp_control_tool_ignored indicates that the tool has ignored the specified command. A tool may return other positive values strictly greater than 64 that are tool-defined.

Execution Model Events

The tool-control event occurs in the thread that encounters a call to omp_control_tool at a point inside its corresponding OpenMP region.

Tool Callbacks

A thread dispatches a registered ompt_callback_control_tool callback for each occurrence of a tool-control event. The callback executes in the context of the call that occurs in the user program and has type signature ompt_callback_control_tool_t. The callback may return any non-negative value, which will be returned to the application by the OpenMP implementation as the return value of the omp_control_tool call that triggered the callback.

Arguments passed to the callback are those passed by the user to omp_control_tool. If the call is made in Fortran, the tool will be passed NULL as the third argument to the callback. If any of the four standard commands is presented to a tool, the tool will ignore the modifier and arg argument values.

Restrictions

Restrictions on access to the state of an OpenMP first-party tool are as follows:

Cross References