| Function | Classification | Cancel | ISR | Signal | Thread |
|---|---|---|---|---|---|
| hcreate() | POSIX 1003.1 XSI | No | No | No | Yes |
| hdestroy() | POSIX 1003.1 XSI | No | No | No | Yes |
| herror() | Unix | Yes | No | No | No |
| hsearch() | POSIX 1003.1 XSI | No | No | Yes | Yes |
| hstrerror() | Unix | No | No | Yes | Yes |
| htonl() | POSIX 1003.1 | No | Yes | Yes | Yes |
| htons() | POSIX 1003.1 | No | Yes | Yes | Yes |
| hwi_find_item() | QNX Neutrino | No | Yes | Yes | Yes |
| hwi_find_tag() | QNX Neutrino | No | Yes | Yes | Yes |
| hwi_next_item() | QNX Neutrino | No | Yes | Yes | Yes |
| hwi_next_tag() | QNX Neutrino | No | Yes | Yes | Yes |
| hwi_off2tag() | QNX Neutrino | No | Yes | Yes | Yes |
| hwi_tag2off() | QNX Neutrino | No | Yes | Yes | Yes |
| hypot() | ANSI POSIX 1003.1 | No | No | No | Yes |
| hypotf() | ANSI POSIX 1003.1 | No | No | No | Yes |