PMSTRNCAT(3)

✨ pmstrncat — bestie edition 💖

okay so real talk, this is the pmstrncat page from the PCP (Performance Co-Pilot) library functions manual, and it's literally about safe string concatenation. no cap. let's get into it 🫶

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🌸 NAME 🌸

pmstrncat — safe string concatenation, fr fr 💅

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🎀 C SYNOPSIS 🎀

#include <pcp/pmapi.h>

int pmstrncat(char *dest, size_t destlen, char *src);

cc ... -lpcp

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✨ DESCRIPTION ✨

so pmstrncat is a safe string concatenation routine whose semantics are similar to strncat(3). similar. not the same. bestie, they are NOT the same, and that's the whole point 👑

the main differences between pmstrncat and strncat(3) are, and I'm listing them all because you deserve to know:

• src must be null-byte terminated for pmstrncat ⚠️
• destlen is the length of the destination buffer (dest) for pmstrncat, not the maximum number of non-null bytes to copy from src as it is for strncat
• the length argument has the same semantics for pmstrncat and pmstrncpy(3), unlike strncat(3) and strncpy(3) — consistency slay 💖
• the return value from pmstrncat is useful (iconic behaviour, honestly)
• the order of the arguments for pmstrncat has been deliberately changed from the order of the arguments for strncat(3) to avoid accidental misuse that a compiler can easily detect 🔥

On success, pmstrncat returns 0, else -1 indicates that src is too big and the result has been truncated to ensure dest has not been overrun. so like, it protects you. it's giving bodyguard energy 🛡️✨

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🦋 HISTORY 🦋

strncat(3) first appeared in Edition 7 AT&T Unix around 1979. and ngl, it was specifically crafted to construct file pathnames (which needed to be null-byte terminated) from component names from on-disk directory entries that were of a fixed maximum size and may have zero, one or more trailing null-bytes. very niche. very 1979. 💀

the subsequent attempts to use strncat(3) for more general string concatenation operations have been fraught with abuse and security issues 😭 and pmstrncat is an attempt to address these problems. it's the glow-up the function always needed.

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🌈 SEE ALSO 🌈

PMAPI(3), pmstrncpy(3), strncat(3) and strncpy(3) 🫶

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and that's the whole page, bestie!! brought to you by Performance Co-Pilot (PCP) — mwah, go write some safe concatenation 💖✨🎀