Runtime interface functions
Your foreign subroutines can access the C string and data conversion functions, which are part of the Synergy runtime. You can only use these functions when you build a DLL or shared object with C routines (see Building a dynamic library with C routines).
You must pass the argument block pointer to runtime interface functions. This argument block pointer gets passed to your C routine. More than one argument block pointer can be active. For example, the following call is valid (from Synergy DBL):
xcall csub(%cfunc1, %cfunc2(%cfunc3))
Example using the Synergy DBL C interface
The example below illustrates the following:
- A user-supplied C subroutine called from a Synergy program
- A Synergy DBL subroutine called from a user-supplied C subroutine
; ; Calculate x to the yth power through the use of the system-supplied ; subroutine pow() in the C routine pwrrti.c. ; .define TTCHN ,1 record input ,a30 xval ,d10 yval ,d10 result ,d10 rlen ,d2 proc open(TTCHN, o, "tt:") repeat begin display(TTCHN, "x: ") reads(TTCHN, input) [eof=done] xval = input display(TTCHN, "y: ") reads(TTCHN, input) [eof=done] yval = input xcall power(result, xval, yval) input = result [left:rlen] writes(TTCHN, "(DBL) result: " + input(1:rlen)) end done, end subroutine sub1 a_result ,n proc writes(TTCHN, "(C) result: " + %string(a_result)) return endsubroutine /* --------------------------------------------------------------------- * * Routine: XCALL POWER(RESULT, IVAL, POWR) * * Description: Calculate X to the nth power, display the result * with a Synergy program, and return the result to * the calling routine. * * Arguments: RESULT, D; the result with size defined in the * Synergy program limited to D10 * * IVAL, D; Decimal value X * POWR, D; Power value n * * Requirements: UNIX - link with -lm (math library) * * Notes: * * To identify this routine, like .IDENT, declare a variable * in the form: * * static char *var = "@(#)ident"; * * The runtime executable will contain the ident string and can * be seen with the "what" command (e.g., what $DBLDIR/bin/dbr). * * ------------------------------------------------------------------ */ #include <math.h> #include "xcall.h" #define WROARG 6 static char *what = "@(#)POWER V2.0 (C-interface)"; extern double pow(); void power(argblk) DESCRIP **argblk; { double num1, num2, result; SEGENTRY *segp; /* SEGENTRY & DESC are DESCRIP *exec_argblk[2]; * defined in xcall.h */ DESCRIP r_descr; if ((long)argblk[0] != 3) /* Expecting 3 args */ dblerror(WROARG); num1 = get_xarg_fval(argblk, 2); /* Get the x and n */ num2 = get_xarg_fval(argblk, 3); /* arguments */ result = pow(num1, num2); /* Call pow function */ put_xarg_fval(argblk, 1, result); /* Load return val */ /* Set up a pointer to our return argument pairs to Synergy sub1 */ exec_argblk[0] = (DESCRIP *)1; /* Define one argument */ exec_argblk[1] = get_xarg(argblk, 1, &r_descr); dbl_exec(get_seg_ptr("SUB1"), exec_argblk); /* Call Synergy subroutine */ return; }