The first step when creating a C++ database application is to perform all of the necessary OCI initializations and allocations. These steps are required for all OCI applications, as the following code illustrates. This init_env_handle() function creates and initializes the OCI environment that requires an allocation of several handles that will be populated by the subsequent member functions. This function is not application-specific and thus can be used as-is in your applications.
/*--------------------------------------------------------*/
/* Initialize the environment and allocate handles */
/*--------------------------------------------------------*/
sb4 ociapi::init_env_handle()
{ sword status = 0;
/* Environment initialization and creation */
if (OCIEnvCreate((OCIEnv **) &envhp, (ub4) OCI_OBJECT, (dvoid *) 0,
(dvoid * (*)(dvoid *,size_t)) 0,
(dvoid * (*)(dvoid *, dvoid *, size_t)) 0,
(void (*)(dvoid *, dvoid *)) 0, (size_t) 0, (dvoid **) 0))
{ printf("FAILED: OCIEnvCreate()\n");
return OCI_ERROR;
}
/* allocate error handle */
if (OCIHandleAlloc( (dvoid *)envhp, (dvoid **) errhp,
(ub4) OCI_HTYPE_ERROR, (size_t) 0, (dvoid **) 0))
{ printf("FAILED: OCIHandleAlloc() on errhp\n");
return OCI_ERROR;
}
/* allocate server handle */
if (status = OCIHandleAlloc( (dvoid*)envhp, (dvoid **) &srvhp,
(ub4) OCI_HTYPE_SERVER, (size_t) 0, (dvoid **) 0))
{ printf("FAILED: OCIHandleAlloc() on srvhp\n");
checkerr( errhp, status);
return OCI_ERROR;
}
/* allocate service context handle */
if (status = OCIHandleAlloc(( dvoid*)envhp, (dvoid **) &svchp,
(ub4) OCI_HTYPE_SVCCTX, (size_t) 0, (dvoid **) 0))
{ printf("FAILED: OCIHandleAlloc() on svchp\n");
checkerr( errhp, status);
return OCI_ERROR;
}
/* allocate session handle */
if (status = OCIHandleAlloc( (dvoid*)envhp, (dvoid **) &authp,
(ub4) OCI_HTYPE_SESSION, (size_t) 0, (dvoid **) 0))
{ printf("FAILED: OCIHandleAlloc() on authp\n");
checkerr( errhp, status);
return OCI_ERROR;
}
/* Allocate statement handle */
if (status = OCIHandleAlloc( (dvoid*)envhp, (dvoid **) stmthp,
(ub4) OCI_HTYPE_STMT, (size_t) 0, (dvoid **) 0))
{ printf("FAILED: OCIHandleAlloc() on stmthp\n");
checkerr( errhp, status);
return OCI_ERROR;
}
return OCI_SUCCESS;
}