NAME

       gd_validate — check a dirfile field code for validity

SYNOPSIS

       #include <getdata.h>

       int gd_validate(DIRFILE *dirfile, const char *field_code);

DESCRIPTION

       The  gd_validate()  function queries a dirfile(5) database specified by dirfile and checks
       whether field_code, which may contain a representation suffix, specifies a valid field.

       The dirfile argument must point to a valid DIRFILE object previously created by a call  to
       gd_open(3).

       This  function  checks  whether the field and its input fields (if any) are found, whether
       the representation suffix (if any) is valid, and  also  that  all  non-literal  parameters
       specify valid scalar fields.

RETURN VALUE

       If  all  checks  pass,  gd_validate()  returns zero.  On error, it returns -1 and sets the
       dirfile error to a non-zero error value.  Possible error values are:

       GD_E_BAD_CODE
               The field specified by field_code or one of the fields it uses as  input  was  not
               found in the database.

       GD_E_BAD_DIRFILE
               The supplied dirfile was invalid.

       GD_E_BAD_REPR
               The representation suffix specified in field_code was not recognised.

       GD_E_BAD_SCALAR
               A  non-literal scalar used in the definition of the field or one of its inputs was
               not found, or was not a CONST or CARRAY field.

       GD_E_DIMENSION
               A scalar field was found where a vector field was expected.

       GD_E_RECURSE_LEVEL
               Too many levels of recursion were encountered while trying to resolve  field_code.
               This  usually  indicates  a  circular  dependency  in  field  specification in the
               dirfile.

       The dirfile error may be retrieved by calling gd_error(3).  A descriptive error string for
       the last error encountered can be obtained from a call to gd_error_string(3).

NOTES

       It  is  not necessary to call this function before passing a field code to another GetData
       function: all functions which accept field codes perform these checks themselves.

SEE ALSO

       dirfile(5), gd_getdata(3), gd_error(3), gd_error_string(3), gd_open(3)