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SPDX-License-Identifier: CC-BY-SA-4.0
copyrights:
- Copyright (C) 2020 embedded brains GmbH (http://www.embedded-brains.de)
enabled-by: true
functional-type: function
links:
- role: interface-function
uid: ../if/predict-true
rationale: |
Example: ``if ( ${../if/predict-true:/name}( 99 > i ) ) { ... }``.
The GNU C compiler uses this information for branch optimization.
``builtin-expect-probability`` defaults to 90%.
Note the misleading name: The macro tells the compiler to assume
"the result is 1" not "the result is not 0" as one would expect for
``true``.
references: []
requirement-type: functional
text: |
When the code is compiled with the GNU C compiler,
and the ${../if/predict-true:/name} macro is used as a conditional
in ``if``-expressions and loop expressions,
and ${../if/predict-true:/params[0]/name} after undergoing all possible C
pre-processor substitutions is an integral expression,
the macro shall cause the compiler to assume that by the percentage of
cases defined by ``builtin-expect-probability`` the expression evaluates
to 1.
type: requirement
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