Important Notice

The pages on this site contain documentation for very old MS-DOS software, purely for historical purposes. If you're looking for up-to-date documentation, particularly for programming, you should not rely on the information found here, as it will be woefully out of date.

                                             ◄Up► ◄Contents► ◄Index► ◄Back►
────────────────────────────────────────────────────────────────────────────
 
  Keyword:  _saveregs
 
  Syntax:   _saveregs declarator
 
  Summary:  Saves and restores CPU registers when entering and exiting
            a function.
 
     The _saveregs keyword is useful in any case in which it is not
     certain what the register conventions of the caller might be. For
     instance, _saveregs could be used for a general-purpose function
     that will reside in a dynamic-link library. Because a function in
     a dynamic-link library might be called from any language, you may
     choose not to assume Microsoft C calling conventions in some
     cases.
 
     The _saveregs keyword causes the compiler to generate code that
     saves and restores all CPU registers when entering and exiting the
     specified function. Note that _saveregs does not restore registers
     used for a return value (the AX register, or AX and DX).
 
     It is not possible to declare a function with both the _saveregs
     and the _interrupt attributes.
 
     The following statement declares <funcptr> as a far pointer to a
     function with no arguments, returning a char pointer. The presence
     of _saveregs tells the compiler that the function called through
     <funcptr> saves and restores register contents. In this example,
     the _loadds keyword also tells the compiler that the target
     function loads its own data segment.
 
          char *(_far _saveregs _loadds *funcptr)( void );
                                    -♦-