Fb Uniqueid Pop

Home › Intrinsic Defines › FB_UNIQUEID_POP

FB_UNIQUEID_POP

Intrinsic define (macro) performed by the compiler.

Syntax

__FB_UNIQUEID_POP__( stack-id )

Parameters

• stack-id

Description

Pops an identifier off of stack identified by stack-id (the size of the stack is decreased by 1).
(__FB_UNIQUEID__ allows to get the identifier at the top of the stack, and __FB_UNIQUEID_PUSH__ allows to push a new unique identifier on to the stack)

Note:

- The "stack-id" name itself is a separate namespace from all other symbols. - The stack can only contain "unique identifiers". - "unique identifier" is a name of an fb symbol that is unique to the module, so does not conflict or shadow other symbol names ("unique identifier" will have the form "LT_xxxx" as a name so it might not be completely unique). - fb uses the form "LT_xxxx" internally for labels, symbols, temp variables, etc (so should avoid naming symbols of this form for any program).

When such a stack is no longer in use, it is recommended that it be empty (at the end there must have been applied as many __FB_UNIQUEID_POP__ as __FB_UNIQUEID_PUSH__ for this stack).
At any time of its use, the number of __FB_UNIQUEID_POP__ applied from the beginning must always be less than or equal to the number of __FB_UNIQUEID_PUSH__ applied.

Remarks

Differences from QB

• New to FreeBASIC

See also

• __FB_UNIQUEID_PUSH__
• __FB_UNIQUEID__

Examples

See also __FB_UNIQUEID__ example.

#macro repeat ? ( count )  '' with user named variable

    Scope

        Dim __counter__ As UInteger = count

        While( __counter__)

#endmacro

#macro end_repeat  '' with user named variable

            __counter__ -= 1

        Wend

    End Scope

#endmacro

Print "With user named variable:"

repeat 3

    Print "   outer"

    repeat 2

        Print "   --- inner"

    end_repeat

end_repeat

Print

#undef repeat

#undef end_repeat

#macro repeat ? ( count )  '' with "unique identifier" variable

    __FB_UNIQUEID_PUSH__( ctx )

    Dim __FB_UNIQUEID__( ctx ) As UInteger = count

    While( __FB_UNIQUEID__( ctx ) )

#endmacro

#macro end_repeat  '' with "unique identifier" variable

        __FB_UNIQUEID__( ctx ) -= 1

    Wend

    __FB_UNIQUEID_POP__( ctx )

#endmacro

Print "With ""unique identifier"" variable:"

repeat 3

    Print "   outer"

    repeat 2

        Print "   --- inner"

    end_repeat

end_repeat

Sleep

/' Output:

With user named variable:

   outer

   --- inner

   --- inner

   outer

   --- inner

   --- inner

   outer

   --- inner

   --- inner

With "unique identifier" variable:

   outer

   --- inner

   --- inner

   outer

   --- inner

   --- inner

   outer

   --- inner

   --- inner

'/

The first part of code works, because the '__counter__' variable is defined in a [Scope...End Scope] block and therefore allows nesting.
The second part of code works (without [Scope...End Scope] block) because of using a "unique identifier" (provided by the compiler).

See also __FB_UNIQUEID_PUSH__ example.

---

Category: Intrinsic Defines
Kind: keyword

---

Reproduced from the FreeBASIC Wiki Manual under the GNU Free Documentation License 1.3 — with no Invariant Sections, no Front-Cover Texts and no Back-Cover Texts. Copyright © the FreeBASIC project and wiki contributors. See License.