Dummy function definitions

Create a local copy of the udefsforasm.h header file (./local_mod/base/include/tpf/udefsforasm.h) and add a dummy function definition in the header file for each C function that you create in BAL. You can copy the ./base/include/tpf/udefsforasm.h header file to create your local copy.

A dummy function definition is a definition that just returns to the caller. For example:

For a function that returns a void, code {return;}
For a function that returns a pointer, code {return NULL;}
For a function that returns a structure, return a dummy structure.
For a function that returns a boolean, code {return FALSE;}
For a function that returns an int or a long, code {return 0;}

With the dummy function definition, the compiler can generate function interface information that the z/TPF system uses later when formatting the ECB trace entry. These dummy function definitions are never called by any code.

If you have many C functions that are written in BAL, you might want to arrange your dummy function definitions in some kind of order so that it is easier to determine if a dummy function definition already exists for a function. For example, the cdefsforasm.c program, which is for IBM® use only, contains the function names in alphabetic order with a block comment for each letter.

A dummy function definition is not a function prototype. Table 1 provides examples of z/TPF function prototypes, the value that is returned, and the corresponding dummy function definitions.

Table 1. Dummy function definition examples
Function prototype	Returns	Dummy function definition
`#define facs(r) FACS(r) void FACS(struct TPF_regs *regs);`	void	`void facs(struct TPF_regs *) {return;}`
`void *cinfc(enum t_cinfc type, int number, ...);`	pointer to void	`void *cinfc(enum t_cinfc type, int number, ...) {return NULL;}`
`struct cplkc_RC * call_cplkc(int,void *);`	pointer to structure	`struct cplkc_RC * call_cplkc(int i,void *ptr) {return NULL;}`
`struct mallinfo mallinfo (void);`	structure	`struct mallinfo mallinfo (void) {struct mallinfo mdummy; return mdummy;}`
`boolean bbld_recountNeeded ( );`	boolean	`Boolean Bld_recountNeeded(void) {return FALSE;}`
`int waitc(void);`	integer	`int waitc(void) {return 0;}`
`long get_dump_tag_addr(int, char *);`	long	`long get_dump_tag_addr(int I, char *ptr) {return 0;}`

The udefsforasm.h header file is included by the cdefsforasm.c program. This program, which is for IBM use only, also contains the dummy function definitions for z/TPF and z/TPFDF C functions that are coded in BAL. See program ./base/rt/cdefsforasm.c for more examples of dummy function definitions.

Note: Ensure that you place your dummy function definitions in a local copy of the udefsforasm.h header file and not in the cdefsforasm.c program.