# regcall, Qregcall

Tells the compiler that the __regcall calling convention should be used for functions that do not directly specify a calling convention.

## Syntax

Linux: | -regcall

macOS: | -regcall

Windows: | /Qregcall

## Arguments

None

## Default

OFF | The __regcall calling convention will only be used if a function explicitly specifies it.

## Description

This option tells the compiler that the __regcall calling convention should be used for functions that do not directly specify a calling convention. This calling convention ensures that as many values as possible are passed or returned in registers.

It ensures that __regcall is the default calling convention for functions in the compilation, unless another calling convention is specified in a declaration.

This calling convention is ignored if it is specified for a function with variable arguments.

Note that all __regcall functions must have prototypes.

## IDE Equivalent

None

## Alternate Options

None

Parent topic: Code Generation Options

## See Also

C/C++ Calling Conventions