PRB: A2041 Initializing a Large STRUCT

• Microsoft Macro Assembler for MS-DOS, versions 6.0, 6.1, 6.11

SYMPTOMS

Attempting to initialize a structure causes one or more of the following assembly errors:

   error A2041: string or text literal too long
   error A2039: line too long

CAUSE

MASM 6.x has a 255-character line limit. Even when the initialization spans multiple lines, the entire structure initialization is considered one line and is subject to the 255-character limit.

RESOLUTION

The following sample illustrates three possible workarounds:

• Remove white space, comments, line-continuation characters, and so on, in an effort to reduce the total initialization string to less than 255 characters.
• Break up the STRUCT into helper STRUCTS defining and initializing the sub-STRUCTs. Precede this by a label of the type of the original STRUCT.
• Define a label of the type of the STRUCT and follow this with the individual definition and initialization of each STRUCT member.

MORE INFORMATION

Sample Code

; Assemble /c /Fl and examine list file to verify output.

; To test each case, set the following EQU. Set to 0 to ; demonstrate the A2041 error. Set to 1, 2, 3 to test ; each workaround in turn.

WorkaroundA2041 EQU 0

.MODEL SMALL, C

.NOLIST

INCLUDE WIN.INC

.LIST

;--------------------------------------------------------- ; Example structure adapted from WINDOWS.H

OPENFILENAME STRUCT 1t

    lStructSize           DWORD      ?
    hwndOwner             HWND       ?
    hInstance             HINSTANCE  ?
    lpstrFilter           LPCSTR     ?
    lpstrCustomFilter     LPSTR      ?
    nMaxCustFilter        DWORD      ?
    nFilterIndex          DWORD      ?
    lpstrFile             LPSTR      ?
    nMaxFile              DWORD      ?
    lpstrFileTitle        LPSTR      ?
    nMaxFileTitle         DWORD      ?
    lpstrInitialDir       LPCSTR     ?
    lpstrTitle            LPCSTR     ?
    Flags                 DWORD      ?
    nFileOffset           UINT       ?
    nFileExtension        UINT       ?
    lpstrDefExt           LPCSTR     ?
    lCustData             LPARAM     ?
    lpfnHook              FARPROC    ?
    lpTemplateName        LPCSTR     ?

IF WorkaroundA2041 EQ 2

;--------------------------------------------------------- ; helper STRUCTs derived by breaking up the original ; OPENFILENAME STRUCT

OPENFILENAME_1 STRUCT 1t

    lStructSize           DWORD      ?
    hwndOwner             HWND       ?
    hInstance             HINSTANCE  ?
    lpstrFilter           LPCSTR     ?

OPENFILENAME_2 STRUCT 1t

    lpstrCustomFilter     LPSTR      ?
    nMaxCustFilter        DWORD      ?
    nFilterIndex          DWORD      ?
    lpstrFile             LPSTR      ?

OPENFILENAME_3 STRUCT 1t

    nMaxFile              DWORD      ?
    lpstrFileTitle        LPSTR      ?
    nMaxFileTitle         DWORD      ?
    lpstrInitialDir       LPCSTR     ?

OPENFILENAME_4 STRUCT 1t

    lpstrTitle            LPCSTR     ?
    Flags                 DWORD      ?
    nFileOffset           UINT       ?
    nFileExtension        UINT       ?

OPENFILENAME_5 STRUCT 1t

    lpstrDefExt           LPCSTR     ?
    lCustData             LPARAM     ?
    lpfnHook              FARPROC    ?
    lpTemplateName        LPCSTR     ?

ENDIF

.DATA

IF WorkaroundA2041 EQ 0

;--------------------------------------------------------- ; This STRUCT definition and initialization generates: ; error A2041: string or text literal too long ; error A2039: line too long

    ofn OPENFILENAME { SIZEOF(OPENFILENAME), ; lStructSize DWORD
                       NULL,    ; hwndOwner         HWND
                       NULL,    ; hInstance         HINSTANCE
                       NULL,    ; lpstrFilter       LPCSTR
                       NULL,    ; lpstrCustomFilter LPSTR
                       0,       ; nMaxCustFilter    DWORD
                       0,       ; nFilterIndex      DWORD
                       NULL,    ; lpstrFile         LPSTR
                       0,       ; nMaxFile          DWORD
                       NULL,    ; lpstrFileTitle    LPSTR
                       0,       ; nMaxFileTitle     DWORD
                       NULL,    ; lpstrInitialDir   LPCSTR
                       NULL,    ; lpstrTitle        LPCSTR
                       0,       ; Flags             DWORD
                       0,       ; nFileOffset       UINT
                       0,       ; nFileExtension    UINT
                       NULL,    ; lpstrDefExt       LPCSTR
                       0,       ; lCustData         LPARAM
                       NULL,    ; lpfnHook          FARPROC
                       NULL }   ; lpTemplateName    LPCSTR

IF WorkaroundA2041 EQ 1

;--------------------------------------------------------- ; This STRUCT definition and initialization will assemble ; due to keeping the total character count down - removing ; comments, white space, line continuation characters, etc.

    ofn OPENFILENAME { SIZEOF(OPENFILENAME), NULL, NULL,
    NULL, NULL, 0, 0, NULL, 0, NULL, 0, NULL, NULL, 0, 0,
    0, NULL, 0, NULL, NULL }

IF WorkaroundA2041 EQ 2

;--------------------------------------------------------- ; This STRUCT definition and initialization will assemble ; by breaking up the original STRUCT and declaring the ; STRUCTs derived from this breakup. This is preceded by ; defining a LABEL to refer to the entire region of memory. ;

    ofn LABEL OPENFILENAME

    OPENFILENAME_1 { SIZEOF(OPENFILENAME), ; DWORD lStructSize
                     NULL,    ; hwndOwner         HWND
                     NULL,    ; hInstance         HINSTANCE
                     NULL }   ; lpstrFilter       LPCSTR
    OPENFILENAME_2 { NULL,    ; lpstrCustomFilter LPSTR
                     0,       ; nMaxCustFilter    DWORD
                     0,       ; nFilterIndex      DWORD
                     NULL }   ; lpstrFile         LPSTR
    OPENFILENAME_3 { 0,       ; nMaxFile          DWORD
                     NULL,    ; lpstrFileTitle    LPSTR
                     0,       ; nMaxFileTitle     DWORD
                     NULL }   ; lpstrInitialDir   LPCSTR
    OPENFILENAME_4 { NULL,    ; lpstrTitle        LPCSTR
                     0,       ; Flags             DWORD
                     0,       ; nFileOffset       UINT
                     0    }   ; nFileExtension    UINT
    OPENFILENAME_5 { NULL,    ; lpstrDefExt       LPCSTR
                     0,       ; lCustData         LPARAM
                     NULL,    ; lpfnHook          FARPROC
                     NULL }   ; lpTemplateName    LPCSTR

IF WorkaroundA2041 EQ 3

;--------------------------------------------------------- ; This STRUCT definition and initialization will assemble ; by defining a LABEL to refer to a region of memory ; followed by explicitly declaring data for each of the ; members of the STRUCT.

    ofn LABEL OPENFILENAME

        DWORD      SIZEOF(OPENFILENAME) ; lStructSize
        HWND       NULL                 ; hwndOwner
        HINSTANCE  NULL                 ; hInstance
        LPCSTR     NULL                 ; lpstrFilter
        LPSTR      NULL                 ; lpstrCustomFilter
        DWORD      0                    ; nMaxCustFilter
        DWORD      0                    ; nFilterIndex
        LPSTR      NULL                 ; lpstrFile
        DWORD      0                    ; nMaxFile
        LPSTR      NULL                 ; lpstrFileTitle
        DWORD      0                    ; nMaxFileTitle
        LPCSTR     NULL                 ; lpstrInitialDir
        LPCSTR     NULL                 ; lpstrTitle
        DWORD      0                    ; Flags
        UINT       0                    ; nFileOffset
        UINT       0                    ; nFileExtension
        LPCSTR     NULL                 ; lpstrDefExt
        LPARAM     0                    ; lCustData
        FARPROC    NULL                 ; lpfnHook
        LPCSTR     NULL                 ; lpTemplateName

END