Defined Values for waveform
| IVIFGEN_VAL_WFM_SINE | Produce a sinusoid waveform. |
| IVIFGEN_VAL_WFM_TRIANGLE | Produce a triangle waveform. |
| IVIFGEN_VAL_WFM_RAMP_DOWN | Produce a negative ramp waveform. |
| IVIFGEN_VAL_WFM_SQUARE | Produce a square waveform. |
| IVIFGEN_VAL_WFM_RAMP_UP | Produce a positive ramp waveform. |
| IVIFGEN_VAL_WFM_DC | Produce a DC waveform. |