Obtains the key names for a given associative array.

long wvh_askeys(asarr_wvh, keys)

WVH asarr_wvh

char **keys

asarr_wvh—A PV-WAVE variable handle for an existing PV‑WAVE ASARR variable.

keys—A pointer to an array of character pointers large enough to hold all of the keys in the ASARR.

OPI_SUCCESS—Successful assignment occurred.

OPI_FAILURE—The arguments are invalid or inconsistent.

OPI_DO_NOT_PROCEED—Catastrophic errors occurred and execution should not continue. The calling C-code should do its cleaning up (free malloc’s space, free handles, etc.) and return to its caller immediately.

The PV-WAVE ASARR variable you pass in must already exist in your PV‑WAVE session, either retrieved by your C routine or created by wave_assign_asarr.

The keys parameter should be declared as a char ** with enough space allocated to hold a character pointer for each key in the ASARR. You may use the wvh_nelems() routine to determine programmatically how many keys an ASARR contains. The easiest way is to declare it in your routine is:

char *keys[20];  /* where the ASARR holds 20 or fewer keys. */

PV-WAVE allocates the individual key strings and places them in the provided space. You need to free these when you are done with them.

wvh_askeys currently supports only the C language interface.

For more information and example usage, see the example OPI in the wave/demo/interapp/opilist-1_0 directory.

For more general information about creating PV-WAVE variables in your C routine, see the documentation for the wave_assign_* routines.