| Value | Meaning |
|---|---|
| UTF8PROC_BOUNDCLASS_START0 | < Start |
| UTF8PROC_BOUNDCLASS_OTHER1 | < Other |
| UTF8PROC_BOUNDCLASS_CR2 | < Cr |
| UTF8PROC_BOUNDCLASS_LF3 | < Lf |
| UTF8PROC_BOUNDCLASS_CONTROL4 | < Control |
| UTF8PROC_BOUNDCLASS_EXTEND5 | < Extend |
| UTF8PROC_BOUNDCLASS_L6 | < L |
| UTF8PROC_BOUNDCLASS_V7 | < V |
| UTF8PROC_BOUNDCLASS_T8 | < T |
| UTF8PROC_BOUNDCLASS_LV9 | < Lv |
| UTF8PROC_BOUNDCLASS_LVT10 | < Lvt |
| UTF8PROC_BOUNDCLASS_REGIONAL_INDICATOR11 | < Regional indicator |
| UTF8PROC_BOUNDCLASS_SPACINGMARK12 | < Spacingmark |
| UTF8PROC_BOUNDCLASS_PREPEND13 | < Prepend |
| UTF8PROC_BOUNDCLASS_ZWJ14 | < Zero Width Joiner |
| UTF8PROC_BOUNDCLASS_E_BASE15 | < Emoji Base |
| UTF8PROC_BOUNDCLASS_E_MODIFIER16 | < Emoji Modifier |
| UTF8PROC_BOUNDCLASS_GLUE_AFTER_ZWJ17 | < Glue_After_ZWJ |
| UTF8PROC_BOUNDCLASS_E_BASE_GAZ18 | < E_BASE + GLUE_AFTER_ZJW |
| UTF8PROC_BOUNDCLASS_EXTENDED_PICTOGRAPHIC19 | |
| UTF8PROC_BOUNDCLASS_E_ZWG20 |