NOTE: In this table, hu is a type HeaderUnit that was returned from a previous call to fh_create() or fh_ehu(), fd is an open file descriptor (type int) returned by a previous call to open(), and idx is a double floating point sorting number used internally by the library. Finally, where-ever name and comment are found, these are ASCII character strings (type char*). They must contain only those characters allowed by the FITS standard.
| Return | Function | Parameters | Description |
| HeaderUnit | fh_create | No parameters | Allocate a table to store FITS cards. |
| HeaderUnit | fh_copy_hu | (HeaderUnit hu) | Allocate a table to store FITS cards and copy an initial set from `hu'. |
| fh_result | fh_destroy | (HeaderUnit hu) | Free memory associated with `hu'. Check return! |
| fh_result | fh_read | (HeaderUnit hu, int fd, double idx) | Read header from an open file descriptor. |
| fh_result | fh_reindex | (HeaderUnit hu) | Restore fh_registry.h indices to the cards in `hu'. |
| fh_result | fh_file | (HeaderUnit hu, const* filespec, fh_mode) | Open and read header from a file or extension. |
| int | fh_file_desc | (HeaderUnit hu) | Get the file descriptor used by fh_file |
| fh_result(??) | fh_reserve | (hu, int n) | Reserve at least n cards slots for downstream use. |
| fh_result | fh_validate | (hu) | Test if `hu' is complete and valid (fh_validate.c) |
| fh_result | fh_count_cards | (hu) | Put library in special mode to count cards |
| fh_result | fh_write | (hu, fd) | Write header, padding, and END to an open file. |
| fh_result | fh_write_padding | (hu, fd) | Write padding to go after the IMAGE. |
| fh_result | fh_write_padded_image | (hu, fd, void* data, size, typesize) | Write `size' image bytes of `data' plus padding. |
| fh_result | fh_read_padded_image | (hu, fd, void* data, size, typesize) | Read `size' bytes into user allocated `data'. |
| fh_result | fh_copy_padded_image | (hu, fd_out, fd_in) | Copy image and padding from another open file. |
| fh_result | fh_rewrite | (hu) | Write the header back to the original file, if possible. |
| Return | Function | Parameters | Description |
| int | fh_extensions | (hu) | Reads NEXTEND to determine number of extensions. |
| int | fh_image_bytes | (hu) | Reads BITPIX and NAXIS* to find (unpadded) image size. |
| int | fh_image_blocks | (hu) | Converts fh_image_bytes to size in 2880-byte blocks. |
| int | fh_header_blocks | (hu) | Returns size required for header in 2880-byte blocks. |
| HeaderUnit | fh_ehu | (hu, int number) | Seek to extension by its offset in the file (caution!) |
| HeaderUnit | fh_ehu_by_imageid | (hu, int imageid) | Seek to extension with matching IMAGEID keyword. |
| HeaderUnit | fh_ehu_by_extname | (hu, char* extname) | Seek by EXTNAME (e.g. ``im07'' or ``chip03b'') |
| Return | Function | Parameters | Description |
| fh_result | fh_get_bool | (hu, char* name, fh_bool* value) | *value gets FH_TRUE or FH_FALSE |
| fh_result | fh_get_int | (hu, char* name, int* value) | *value gets integer value of `name' |
| fh_result | fh_get_flt | (hu, char* name, double* value) | *value gets double-float value of `name' |
| fh_result | fh_get_str | (hu, char* name, char* value, maxlen) | *value gets string value of `name' |
| const char* | fh_first | (hu) | Returns the first 80 character record (or NULL) |
| const char* | fh_next | (hu) | Returns the next 80 character record (or NULL) |
| double | fh_idx | (hu) | Return the index for the card last returned by fh_next . |
| fh_result | fh_search | (hu, char* name, double* idx) | Returns FH_SUCCESS if found (and *idx if !NULL) |
| fh_result | fh_show | (hu) | Display a list on stdout (for debugging). |
| double | fh_idx_after | (hu, char* name) | Get `idx' for a new card after `name' |
| double | fh_idx_before | (hu, char* name) | Get `idx' for new card before `name' |
| Return | Function | Parameters | Description |
| fh_result | fh_remove | (hu, char* name) | Removes a card from the header unit in memory. It will disappear from the file on the next fh_rewrite() |
| fh_result | fh_set_all_units | (hu) | Overrides default behavior of fh_set*() functions so they change extensions too. |
| void | fh_set_com | (hu, idx, char* name, char* comment) | Creates new comment card containing up to 72 ASCII characters. ``name'' should be ``HISTORY'' or ``COMMENT''. |
| void | fh_set_bool | (hu, idx,name, fh_bool value, comment) | Changes or adds the card `name' with new value of 'T' if value is non-zero, and sets comment field if comment is not empty. |
| void | fh_set_int | (hu, idx, name, int value, comment) | Changes or adds keyword `name' with new integer value and comment fields. |
| void | fh_set_flt | (hu, idx, name, double value, double flt, double prec, comment) | Changes or adds keyword `name' with new floating-point value. |
| void | fh_set_str | (hu, idx, name, char* value, comment) | Changes or adds keyword `name' with new string value and comment fields. |
| void | fh_set_val | (hu, idx, name, char* value, comment) | Changes or adds keyword `name' with new pre-formatted value and comment fields. (Use typed functions above instead.) |
| fh_result | fh_merge | (target_hu, source_hu) | Merges all cards from one list into another. Final order depends on the sorting numbers in both lists. |
| Return | Function | Parameters | Description |
| void | fh_log_warning | (fh_logger_t log_function) | Set warning log handler |
| void | fh_log_error | (fh_logger_t log_function) | Set error log handler |
| void | fh_log_perror | (fh_logger_t log_function) | Set system error log handler (check errno) |