ouadji wrote:

one "}" to end "rept", and another "}" to end "struct" ?

Yes. Formatting it like this may help to understand what's going on:

Code:

rept 1
{
     mov eax,eax
     struc myS
     {
       .mydata dd 1
}

       abc myS
     }    

;(A) does compile
rept 1 {
struc m2 { . dd ? }
} 
    

;(B) does not compile
macro m {
struc m2 { . dd ? }
} ;<-- illegal instruction
    

B does not compile because the "struc" is put inside the macro, so once the macro is created it is taken out of the source, leaving the last "}" all by it's self. The "rept" leaves "struc m2 { . dd ?" behind, whereas the macro leaves nothing behind.

;does not compile
macro m {
struc m2 { . dd ? }
}
m ;<-- (incomplete macro)

;---------------------------------------
;does compile
macro m {
struc m2 { . dd ? \}
}