How -to initialise array RESOURCE members

diff -r 80ef3a206772 -r 48780e181b38 Symbian3/SDK/Source/GUID-0142B290-DA6C-5574-83D7-7555D804D9B5.dita --- a/Symbian3/SDK/Source/GUID-0142B290-DA6C-5574-83D7-7555D804D9B5.dita Fri Jul 16 17:23:46 2010 +0100 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000 @@ -1,75 +0,0 @@ - - - - - -How -to initialise array RESOURCE members -

<array-initialiser>

array-initialiser ::=

{ <array-initialiser-item-comma-list> } <array-initialiser-item>

array-initialiser-item ::=

<initialiser>

Fixed-length arrays

If a member is declared as a fixed-length array in the STRUCT or RESOURCE definition, -for example,

-WORD elements[10] -

then you must not specify any more items than were given in the length.

If fewer items are specified in the default initialisation (i.e. in the STRUCT definition), -then an error also results.

Note that no values will be given to unspecified elements at the end of -the array, even if they have been default initialised in the STRUCT definition. -Take the following example:

-STRUCT SAMPLE - { - BYTE bts[3]={1,2,3}; - } -

In the following resource:

-RESOURCE SAMPLE default - {} -

the output will be the whole default array

-0x01 0x02 0x03 -

but in this resource:

-RESOURCE SAMPLE first_specified - { - bts={5}; - } -

the output is:

-0x05 -

with the second and third elements lost.

If you specify only the second element in the RESOURCE definition, -then the first element is taken from the default initialisation, the second -from the explicit initialisation and the third element is lost. The following -resource:

-RESOURCE SAMPLE second_specified - { - bts[1]=5; - } -

results in the 2-byte output:

-0x01 0x05 -

If, however, you explicitly initialise an element in the middle of an array -without having supplied default values for array members before it, then an -error will result.

Using expressions to initialise array elements

You -may initialise array elements with expressions. You must explicitly initialise -each member component of the array otherwise the expressions will be evaluated -incorrectly. The following resource:

RESOURCE SAMPLE correct_expression - { - bts[0]=3+1; - bts[1]=2; - bts[2]=3; - }

will generate the correct output 0x04 0x02 0x03. -However, if you use the following syntax:

RESOURCE SAMPLE incorrect_expression - { - bts={3+1,2,3}; - }

the output will be 0x03 0x02 0x03. This -is because the pre-processor treats 3+1 as a literal string -that is then interpreted by the compiler as 3. In the resource correct_expression above -the ‘=‘ sign forces the pre-processor to evaluate the expression.

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