6.3.2 Inline Expansion of Subprograms
1
[Subprograms may be expanded in line at the call
site.]
Syntax
2
{program
unit pragma (Inline) [partial]} {pragma,
program unit (Inline) [partial]} The form
of a
pragma Inline, which is a program unit
pragma (see
10.1.5), is as follows:
3
pragma Inline(
name
{,
name});
Legality Rules
4
The pragma shall apply
to one or more callable entities or generic subprograms.
Static Semantics
5
If a pragma Inline applies
to a callable entity, this indicates that inline expansion is desired
for all calls to that entity. If a pragma
Inline applies to a generic subprogram, this indicates that inline expansion
is desired for all calls to all instances of that generic subprogram.
5.a
Ramification:
Note that inline expansion is desired no matter what name is used
in the call. This allows one to request inlining for only one of several
overloaded subprograms as follows:
5.b
package IO is
procedure Put(X : in Integer);
procedure Put(X : in String);
procedure Put(X : in Character);
private
procedure Character_Put(X : in Character) renames Put;
pragma Inline(Character_Put);
end IO;
5.c
with IO; use IO;
procedure Main is
I : Integer;
C : Character;
begin
...
Put(C); -- Inline expansion is desired.
Put(I); -- Inline expansion is NOT desired.
end Main;
5.d
Ramification: The meaning of a subprogram
can be changed by a
pragma Inline only in
the presence of failing checks (see
11.6).
Implementation Permissions
6
For each call, an implementation is free to follow
or to ignore the recommendation expressed by the pragma.
6.a
Ramification: Note, in particular, that
the recommendation cannot always be followed for a recursive call, and
is often infeasible for entries. Note also that the implementation can
inline calls even when no such desire was expressed by a pragma, so long
as the semantics of the program remains unchanged.
6.1/2
{
AI95-00309-01}
An implementation may allow a pragma
Inline that has an argument which is a direct_name
denoting a subprogram_body of the same declarative_part.
6.b/2
Reason: This is
allowed for Ada 83 compatibility. This is only a permission as this usage
is considered obsolescent.
6.c/2
Discussion: We
only need to allow this in declarative_parts,
because a body is only allowed in another body, and these all have declarative_parts.
7
6 The name in
a pragma Inline can denote more than one entity
in the case of overloading. Such a pragma
applies to all of the denoted entities.
Incompatibilities With Ada 83
7.a/2
{
AI95-00309-01}
{incompatibilities with Ada 83} A
pragma Inline cannot refer to a subprogram_body
outside of that body. The pragma can be given inside of the subprogram
body. Ada 2005 adds an Implementation Permission to allow this usage
for compatibility (and Ada 95 implementations also can use this permission),
but implementations do not have to allow such pragmas.
Extensions to Ada 83
7.b
{
extensions to Ada 83}
A
pragma Inline is allowed inside a
subprogram_body
if there is no corresponding
subprogram_declaration.
This is for uniformity with other program unit pragmas.
Extensions to Ada 95
7.c/2
{
AI95-00309-01}
{extensions to Ada 95} Amendment
Correction: Implementations are allowed to let Pragma
Inline apply to a subprogram_body.
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