In C programming, what does “emit” do?

问题:

I recently tried to expand my knowledge of the C language and I came across a program that used emit, to possibly emit a byte.

__declspec(naked) void marker_begin() {
__asm {
    _emit 0x51;
    _emit 0x21;
    _emit 0x1A;
    _emit 0x14;
    _emit 0x2C;
    _emit 0x5B;
}

}

What could this be used for? Thanks in advance.

回答1:

Your C program is executing inline assembly code by using the _asm keyword. _asm is a Microsoft specific keyword used in MSDN. The __asm keyword invokes the inline assembler. It must be followed by an assembly instruction, a group of instructions enclosed in braces, or, at least, an empty pair of braces.

The _emit pseudo instruction is similar to the DB directive of MASM. _emit is an MSDN specific pseudo instruction. _emit is used to define a single immediate byte at the current location in the current text segment. _emit can define only one byte at a time and only in the text segment.