Programming Guide - Actian

ProceduresGuidelines for Writing C ProceduresUse the following syntax when writing a C procedure:procname([parameters]){processing statements}Note: You cannot name your C procedure “main,” and the procedure must notbe static. You can call any C procedure from 4GL except the “main” function.Follow these guidelines for passing parameters to C procedures:• Pass an integer as four bytes by value (or by reference if byref isspecified).• Pass a smallint as four bytes by value (or by reference if byref isspecified).• Pass a float as a double-format float by value (or by reference, if byref isspecified).To ensure full portability, pass all floating point parameters to Cprocedures using the byref qualifier. For example, the following codefragment declares some variables and calls a C procedure, passing theprocedure a floating-point parameter:/* variable declarations */test_float = float;test_integer = integer;test_return = integer...test_return = callproc myCproc (test_integer,byref(test_float));The corresponding C procedure is declared as follows:LongmyCproc (ivalue, fvalue)long ivalue;double *fvalue;{processing statements}• Pass a string as a pointer to a null-terminated string as follows:– Pass fixed-length string types (c, char) with trailing blanks up to theirfull length.– Pass variable-length string types (text, varchar) without trailingblanks.82 Programming Guide