In Windows, applications and libraries contain some
information which are necessary to make APIs such as
GetProcAddress work. So it is necessary to
duplicate these data structures in the Unix world to make these
same APIs work with Winelib applications and libraries.
The spec file is there to solve the semantic gap described above. It provides information about each API exported from a DLL so that the appropriate tables can be generated. Further the information is used to for better relay logging.
A typical spec file will look something like this:
@ stdcall -private DllCanUnloadNow() @ stdcall -private DllGetClassObject(ptr ptr ptr) @ stdcall -private DllRegisterServer() @ stdcall -private DllUnregisterServer()
Here is a more detailed description of the spec file format.
# comment text
Anything after a '#' will be ignored as comments.
ORDINAL FUNCTYPE OPTIONS EXPORTNAME([ARGTYPE [ARGTYPE [...]]]) HANDLERNAME @ stdcall CreateDesktopW(wstr wstr ptr long long ptr) @ stdcall CM_Get_Parent(ptr long long) setupapi.CM_Get_Parent @ cdecl -arch=x86_64 ceilf(float) MSVCRT_ceilf
This field can be present zero or more times. Each instance defines a function entry point. The prototype defined by EXPORTNAME ([ARGTYPE [ARGTYPE [...]]]) specifies the name available for dynamic linking and the format of the arguments. ORDINAL is replaced by the ordinal number corresponding to the function, or @ for automatic ordinal allocation (Win32 only).
FUNCTYPE should be one of:
for a Win16 function
for a normal Win32 function
for a Win32 function using the C calling convention
for a Win32 function taking a variable number of arguments
for a Win32 function using the C++ calling convention
ARGTYPE should be one of:
for a 16-bit word
for a 16-bit signed word
for a segmented pointer
for a segmented pointer to a null-terminated string
a 32-bit value
for a linear pointer
for a linear pointer to a null-terminated string
for a linear pointer to a null-terminated wide (16-bit Unicode) string
a 64-bit value
a 128-bit value
a 32-bit floating-point value
a 64-bit floating-point value
For Win32 functions word, s_word, segptr and segstr are not valid. HANDLERNAME is the name of the actual Wine function that will process the request in 32-bit mode.
Strings should almost always map to str, wide strings to wstr. As the general rule it depends on whether the parameter is IN, OUT or IN/OUT.
It is for debug messages. If the parameter is OUT it might not be initialized and thus it should not be printed as a string.
To declare a function using a variable number of arguments in
Win16, specify the function as taking no arguments. The arguments
are then available with CURRENT_STACK16->args. In Win32, specify
the function as varargs and declare it with a
"..." parameter in the C file. See the
wsprintf* functions in
user32.spec for an example.
ORDINAL stub EXPORTNAME
This field can be present zero or more times. Each instance defines a stub function. It makes the ordinal available for dynamic linking, but will terminate execution with an error message if the function is ever called.
ORDINAL extern EXPORTNAME SYMBOLNAME
This field can be present zero or more times. Each instance defines an entry that simply maps to a Wine symbol (variable or function); EXPORTNAME will point to the symbol SYMBOLNAME that must be defined in C code. This type only works with Win32.