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DeclareFunctionMBS class

Type Topic Plugin Version macOS Windows Linux Console & Web iOS
class DynamicDeclares MBS Util Plugin 20.3 Yes Yes Yes Yes No
Function: The class for a C function call.
// change path if you like to try this on Windows or Linux
Dim d As New DeclareLibraryMBS("/usr/lib/libz.1.dylib")

// zlibVersion
// ZEXTERN Const char * ZEXPORT zlibVersion Of((void));

Dim p As ptr = d.Symbol("zlibVersion")
Dim f As New DeclareFunctionMBS("()Z", p)

Dim n As String = f.Invoke
MsgBox "zlibVersion: "+n
Compared to built-in declares in Xojo, those functions allow a much more dynamic calling of functions with various calling conventions.

We have
  • more dynamic
  • the possibility to define declares at runtime
  • more calling conventions
  • support for variable arguments in C (dots in argument list)
  • thread safe callbacks with DeclareCallBackMBS class.

Feedback, Comments & Corrections

Call Modes

Constant Value Description
kCallModeCArm64 22 C arm64 call (AArch64)
kCallModeCArmArmhf 30 C arm call (arm hardfloat - e.g. raspberry pi)
kCallModeCDefault 0 C default function call for current platform
kCallModeCEllipsis 100 C ellipsis function call (named arguments (before ’...’))
kCallModeCEllipsisVarargs 101 C ellipsis function call (variable/unnamed arguments (after ’...’))
kCallModeCX64Win64 7 C x64 Windows standard call
kCallModeCX86Cdecl 1 C x86 platforms standard call
kCallModeCX86Win32FastGnu 4 C x86 Windows GCC fast call
kCallModeCX86Win32FastMs 3 C x86 Windows Microsoft fast call
kCallModeCX86Win32Std 2 C x86 Windows standard call
kCallModeCX86Win32ThisGnu 6 C x86 Windows GCC this call
kCallModeCX86Win32ThisMs 5 C x86 Windows Microsoft this call
kCallModeSysDefault 200 C default syscall for current platform
kCallModeSysX64SyscallSysV 204 C syscall for x64 System V platforms
kCallModeSysX86Int80HBSD 202 C syscall for x86 BSD platforms
kCallModeSysX86Int80HLinux 201 C syscall for x86 Linux

Calling Conventions

Constant Value Description
kCallModeEllipsis "e" C ellipsis function call
kCallModeFastCallGNU "f" C x86 Windows GCC fast call
kCallModeFastCallMS "F" C x86 Windows Microsoft fast call
kCallModePrefix "_" The character to indicate that next character in the signature is a calling convention prefix.
kCallModeStdCall "s" C x86 Windows standard call
kCallModeThisCallMS "+" C x86 Windows Microsoft this call


Constant Value Description
kTypeBool "B" bool
kTypeChar "c" char, 8 bit signed byte
kTypeDouble "d" Double, 64-bit and 8 bytes big.
kTypeEndArg ")" end of arguments symbol.
kTypeFloat "f" Single, 32-bit and 4 bytes big.
kTypeInt "i" 32-bit signed integer.
kTypeInt64 "l" 64-bit signed integer.
kTypeLong "j" 32/64-bit signed integer.
64-bit only for MacOS and Linux in 64-bit application.
Always 32-bit on Windows.
kTypePtr "p" Pointer. Maybe a reference to an object or array.
kTypeShort "s" 16-bit signed integer.
kTypeString "Z" C String with zero byte as terminator.
kTypeStruct "T" Structure
kTypeUnsignedChar "C" 8 bit unsigned byte
kTypeUnsignedInt "I" 32-bit unsigned integer.
kTypeUnsignedInt64 "L" 64-bit unsigned integer.
kTypeUnsignedLong "J" 32/64-bit unsigned integer.
64-bit only for MacOS and Linux in 64-bit application.
Always 32-bit on Windows.
kTypeUnsignedShort "S" 16-bit unsigned integer.
kTypeVoid "v" Nothing to return.

This class has no sub classes.

Some examples which use this class:

Blog Entries

The items on this page are in the following plugins: MBS Util Plugin.

DeclareCallBackMBS   -   DeclareLibraryMBS

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