funcolumnlookup(3)

💫 funcolumnlookup(3) — the SAORD Documentation glow-up 💫

okay bestie, sit down, hydrate, because we're talking about FunColumnLookup from the funtools fam — it's the little function that spills the tea on any column you point at. like, name, type, mode, offset, size… the whole ✨dossier✨. no cap.

🌸 NAME 🌸

FunColumnLookup — lookup a Funtools column 💅

🦋 SYNOPSIS 🦋

#include <funtools.h>

int FunColumnLookup(Fun fun, char *s, int which,
                    char **name, int *type, int *mode,
                    int *offset, int *n, int *width)

✨ DESCRIPTION ✨

so the FunColumnLookup() routine is literally the group chat gossip of column info — you hand it a column (by name or by index) and it hands you back everything: the name, the type, the mode, the offset, how many elements, how wide. obsessed. 🫶

first arg is the Fun handle for this whole set of columns. second arg is the name of the column you're looking up. and here's the plot twist: if the name argument is NULL, then the argument right after it is the zero-based index into the column array of the column you want info about. so it's giving "either/or" energy, iykyk.

next up is a pointer to a char *, which is where the name of the column gets dropped. and then the args after that are all addresses of int values, and here's what lands in each one:

• type — the data type of the column, and the menu is:
  • A: ASCII characters
  • B: unsigned 8-bit char
  • I: signed 16-bit int
  • U: unsigned 16-bit int (not standard FITS, bestie, just so you know)
  • J: signed 32-bit int
  • V: unsigned 32-bit int (not standard FITS either, don't come for me)
  • E: 32-bit float
  • D: 64-bit float
• mode — the bit flag status of the column, and the flags are:
  • COL_ACTIVE — 1 — is the column activated?
  • COL_IBUF — 2 — is the column in the raw input data?
  • COL_PTR — 4 — is the column a pointer to an array?
  • COL_READ — 010 — is read mode selected?
  • COL_WRITE — 020 — is write mode selected?
  • COL_REPLACEME — 040 — is this column being replaced by user data?
• offset — the byte offset in the struct 📍
• n — the number of elements (i.e. the size of the vector) in this column
• width — the size in bytes of this column 📏

so if the named column actually exists, the routine returns a positive integer and we're thriving. otherwise it returns zero. (and that positive integer? it's the index+1 into the column array of where this column was located. cute, right?)

now — if you pass NULL as the return address for one (or more) of these values, then no data comes back for that thing. you just skip it, no drama. for example:

if( !FunColumnLookup(fun, "phas", 0, NULL NULL, NULL, NULL, &npha, NULL) )
  gerror(stderr, "can't find phas column\n");

this one only brings back info about the size of the phas vector. minimalist queen. 👑

🌈 SEE ALSO 🌈

peep funtools(7) for the full list of Funtools help pages — it's the master doc, fr fr.

and that's the whole vibe 💖 this was version 1.4.5, dated April 14, 2011, brought to you by the SAORD Documentation girlies. stay hydrated, stay curious, and go look up some columns, bestie 🎀🦋✨