atexpand(3)

💖 atexpand(3) — bestie edition 💖

AtFS Toolkit Library · section 3, the library calls, we love her 💅

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✨ NAME ✨

atExpandAttrs, atExpand — attribute expansion, aka the glow-up machine for your strings 🌸

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🦋 SYNOPSIS 🦋

#include <atfs.h>
#include <atfstk.h>

int atExpandAttrs (Af_key *aso, char *buf, size_t bufSize, FILE *dest,
size_t destSize, int mode);

int atExpand;

yeah that second one is just a variable, no parentheses, she's living her best life 🫶

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👑 DESCRIPTION 👑

okay so, atExpandAttrs goes on a lil scavenger hunt through the char buffer buf, and it looks all the way up to bufSize for strings shaped like $__attributeName — and sometimes that lil guy is followed by a delimiting second dollar sign ($), cute, optional, iconic.

When it finds one of those? Everything in the buffer up to the character right before that first dollar sign gets sent straight to the destination output dest. ✨

Then, if an attribute named attributeName is actually set for the current attributed software object aso, that citation-string gets swapped out for the value of that attribute and appended to the output. slay. 💅

And then — this is the part people miss — output of the buf contents picks back up at the first character after the whitespace character or dollar sign that delimited attributeName. no cap.

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🎀 the string-buffer plot twist 🎀

ngl, the type of the dest argument is "pointer to file structure," but bestie, you can still make atExpandAttrs copy its output into a string buffer instead of an open file. here's the tea 🍓:

• you must pass the constant AT_EXPAND_STRING as the mode argument
• and bufSize must be set to indicate the length of the destination buffer dest (it gets casted to character pointer, don't worry abt it)

🚨 if destSize is too small to hold the result string, atExpandAttrs returns a negative value. beware, she will not be silenced, she will simply say no.

in the regular case — the one where output shall be written to a file — the mode parameter must be AT_EXPAND_FILE. periodt. 🔥

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🧚 the atExpand variable 🧚

the atExpand variable suppresses attribute expansion when set FALSE. (that's the whole personality.)

you can set it:

1. directly from the application program, or
2. indirectly by evaluation of the pseudo attribute citation $__xpoff in any buffer scanned by atExpandAttrs

and then there's her sister $__xpon, another pseudo attribute citation — she cancels the effect of a previous $__xpoff and switches attribute citation back on again. 🔄

⚠️ but lowkey important: $__xpon does not enable attribute citation if it was disabled explicitly by the application program. she can undo her own drama, not yours. 🙈

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💀 DIAGNOSTICS 💀

atExpandAttrs returns -1 on error. and bestie, it doesn't just ghost you — additionally, the atError variable is set, and afErrMsg holds a diagnostic message. the group chat has receipts. 😭

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🌈 SEE ALSO 🌈

• atattribute(3)

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that's the whole page, you're so welcome, go expand some attributes, you absolute main character 👑✨

mwah 💖 — written up by the AtFS Toolkit Library, version AtFStk-1.12, dated Fri Jun 25 16:39:36 1993 (an elder, but a legend fr fr 🎀)