batchlas::ScopedEnvVar Class Reference

Overview

Sets (or unsets) an environment variable for a scope and restores it on exit.

Both the constructor and the destructor call detail::reload_settings(), so the library sees the pinned value immediately and stops seeing it when the scope ends. A raw ::setenv is invisible to batchlas::settings(); use this instead.

{
    ScopedEnvVar pin("BATCHLAS_GEMM_ROUTE", "native");
    gemm(ctx, a, b, c, GemmOptions<float>{});   // runs the native kernel
}

Precondition

name outlives the object (in practice a string literal); it is borrowed, not copied.

Warning

Not thread-safe, because the process environment is not: construct from a test body or benchmark setup, never inside a parallel region. Do not let one straddle a *_buffer_size() query and its solve.

See also

Environment variables

Definition at line 104 of file env.hh.

#include <batchlas/util/env.hh>

Constructors

ScopedEnvVar() [1/2]

batchlas::ScopedEnvVar::ScopedEnvVar ( const char * name, const char * value )

inline

Pin name to value for the scope.

Parameters

name	the variable's name
value	the value to set, or nullptr to unset the variable for the duration (which asks for the automatic route regardless of the surrounding environment)

Definition at line 110 of file env.hh.

~ScopedEnvVar()

batchlas::ScopedEnvVar::~ScopedEnvVar ( )

inline

Restore the previous value (or unset state) and reload the settings.

Definition at line 124 of file env.hh.

ScopedEnvVar() [2/2]

batchlas::ScopedEnvVar::ScopedEnvVar ( const ScopedEnvVar & )

delete

Functions

operator=()

ScopedEnvVar & batchlas::ScopedEnvVar::operator= ( const ScopedEnvVar & )

delete