PMFSTRING(3)

💖 NAME 💖

okay bestie, listen up — pmfstring is your girl for safe string scanning. that's literally it, that's the whole vibe. ✨

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🌸 C SYNOPSIS 🌸

like, here's how you actually use her:

#include <pcp/pmapi.h>

ssize_t pmfstring(FILE *f, char **str);

and when you compile, don't forget:

cc ... -lpcp

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🎀 DESCRIPTION 🎀

so pmfstring is a safe string scanning routine — she does basically the same thing as fscanf(3) with the %s format specifier, but make it responsible. 💅

here's the tea on what she does: she scans the input stream from f, skips over all the initial whitespace characters, and then just... accumulates every subsequent non-whitespace character. like a little vacuum but for chars. 🧹

the main difference (and this is the important part, no cap) is that pmfstring allocates the result buffer str using the malloc(3) family — and she makes sure that str is:

• (a) large enough, and
• (b) null-byte terminated

so you literally never have to worry about that yourself. she handles it. icon behaviour, honestly. 👑

on top of all that, pmfstring does not consider \n to be a whitespace character in that initial scan (the one before filling str). so she will not scan past the end of the current line. this is different from fscanf(3) and — good news — way better aligned with the PCP use cases. fr fr. 🦋

bestie, heads up: you are responsible for maintaining a reference to str, or calling free(3) to release the associated storage. don't be the person who leaks. we don't know her. 🫶

on success, pmfstring returns the length of str — same length strlen(3) would return — and it's guaranteed to be not less than 1. periodt.

if it fails, you get one of these, and str is not assigned a value:

• 0 — meaning no non-whitespace characters were found before the end of the current line from the stream f
• -1 (aka EOF) — meaning end of file on the stream f
• -2 — meaning some more serious failure, probably in the malloc(3) routines; refer to errno for more information 😭

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🌈 COMPATIBILITY 🌈

pmfstring has similar semantics to the %ms format specifier in some versions of fscanf(3), and to the C99 fscanf_s(3) routine. and the tragic part? unfortunately neither of these is portable. 💀 so yeah. that's why she exists.

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⭐ SEE ALSO ⭐

free(3), fscanf(3), malloc(3) and strlen(3).

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k bye, this page came to you straight from Performance Co-Pilot (PCP) — the PMFSTRING(3) girlies know 💜 — mwah, go free your strings 🎀✨