SomVaBuf create

Creates a SOM buffer (somVaBuf) for variable arguments from which the va_list will be built.

Syntax

char       *vb;
int        size;
somVaBuf    rc;

rc = somVaBuf_create(vb, size);

Parameters

vb (char *)

Pointer to user-allocated memory or NULL.

size (int)

Size of memory pointed at by vb, or else zero.

Return Code

rc (somVaBuf)

If successful, somVaBuf is returned; otherwise, a NULL value is returned.

Remarks

This function allocates, if necessary, and initializes a somVaBuf data structure. Memory is allocated if:

• The size parameter is less than the size of the somVaBuf structure,
• The size parameter is zero, or
• The vb parameter is NULL.

Note: Because the somVaBuf data structure is opaque, users cannot determine its size. Although this function accepts a user-allocated buffer, it is recommended that a NULL value be passed as the first argument.

Example Code

C Sample

#include <somobj.h>
void f1(SOMObject obj, Environment *ev)
{
        char *msg;
        va_list start_val;
        somVaBuf vb;
        char *msg1 = "Good Morning";

        vb = (somVaBuf)somVaBuf_create(NULL, 0);
        somVaBuf_add(vb, (char *)&obj, tk_pointer);
                                                  /* target for _set_msg */
        somVaBuf_add(vb, (char *)&ev, tk_pointer);
                                                  /* next argument */
        somVaBuf_add(vb, (char *)&msg1, tk_pointer);
                                                  /* final argument */
        somVaBuf_get_valist(vb, &start_val);
                                                 

        /* dispatch _set_msg on object */
        SOMObject_somDispatch(
                obj,       /* target for somDispatch */
                0,         /* says ignore dispatched method result */
                somIdFromString("_set_msg"), /* the somId for _set_msg */
                start_val); /* target and args for _set_msg */

        /* dispatch _get_msg on obj:   */
        /* Get a fresh copy of the va_list    */
        somVaBuf_get_valist(vb, &start_val);
        SOMObject_somDispatch(
                obj,
                (somToken *)&msg,
                           /* address to store dispatched result */
                somIdFromString("_get_msg"),
                start_val); /* target and arguments for _get_msg */
        printf("%s\n", msg);
        somVaBuf_destroy(vb);
}

C++ Sample

#include <somobj.h>
void f1(SOMObject obj, Environment *ev)
{
        char *msg;
        va_list start_val;
        somVaBuf vb;
        char *msg1 = "Good Morning";

        vb = (somVaBuf)somVaBuf_create(NULL, 0);
        somVaBuf_add(vb, (char *)&obj, tk_pointer);
                                                /* target for _set_msg */
        somVaBuf_add(vb, (char *)&ev, tk_pointer);
                                                      /* next argument */
        somVaBuf_add(vb, (char *)&msg1, tk_pointer);
                                                     /* final argument */
        somVaBuf_get_valist(vb, &start_val);
        
        /* dispatch _set_msg on obj: */
        obj->SOMObject_somDispatch(
                0,         /* says ignore the dispatched method result */
                somIdFromString("_set_msg"), /* the somId for _set_msg */
                start_val);   /* the target and arguments for _set_msg */

        /* dispatch _get_msg on obj:   */
        /* Get a fresh copy of the va_list    */
        somVaBuf_get_valist(vb, &start_val);
        obj->SOMObject_somDispatch(
                (somToken *)&msg,
                           /* address to hold dispatched method result */
                somIdFromString("_get_msg"),
                start_val);   /* the target and arguments for _get_msg */
        printf("%s\n", msg);
        somVaBuf_destroy(vb);
        }

Related

Functions

• somVaBuf_add
• somVaBuf_get_valist
• somVaBuf_destroy
• somvalistGetTarget
• somvalistSetTarget