argz_add(3)

💖 argz_add(3) — Library Functions Manual 💖

okay bestie, sit down, hydrate, because today we're learning about argz vectors and honestly? they're giving "sleeper hit of the glibc catalogue." this page covers argz_add, argz_add_sep, argz_append, argz_count, argz_create, argz_create_sep, argz_delete, argz_extract, argz_insert, argz_next, argz_replace, and argz_stringify — the whole friend group 💅

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✨ NAME ✨

argz_add, argz_add_sep, argz_append, argz_count, argz_create, argz_create_sep, argz_delete, argz_extract, argz_insert, argz_next, argz_replace, argz_stringify — functions to handle an argz list 🦋

📚 LIBRARY 📚

Standard C library (libc, -lc)

🎀 SYNOPSIS 🎀

#include <argz.h>

error_t argz_add(char **restrict argz, size_t *restrict argz_len,
                const char *restrict str);

error_t argz_add_sep(char **restrict argz, size_t *restrict argz_len,
                const char *restrict str, int delim);

error_t argz_append(char **restrict argz, size_t *restrict argz_len,
                const char *restrict buf, size_t buf_len);

size_t argz_count(const char *argz, size_t argz_len);

error_t argz_create(char *const argv[], char **restrict argz,
                size_t *restrict argz_len);

error_t argz_create_sep(const char *restrict str, int sep,
                char **restrict argz, size_t *restrict argz_len);

void argz_delete(char **restrict argz, size_t *restrict argz_len,
                char *restrict entry);

void argz_extract(const char *restrict argz, size_t argz_len,
                char **restrict argv);

error_t argz_insert(char **restrict argz, size_t *restrict argz_len,
                char *restrict before, const char *restrict entry);

char *argz_next(const char *restrict argz, size_t argz_len,
                const char *restrict entry);

error_t argz_replace(char **restrict argz, size_t *restrict argz_len,
                const char *restrict str, const char *restrict with,
                unsigned int *restrict replace_count);

void argz_stringify(char *argz, size_t len, int sep);

🌸 DESCRIPTION 🌸

first things first: these functions are glibc-specific. that's the vibe. no cap, if you're on a different libc, this is not your moment 😭

so. an argz vector is a pointer to a character buffer plus a length. the intended interpretation of that character buffer? it's an array of strings, and the strings are separated by null bytes ('\0'). and here's the rule you cannot skip: if the length is nonzero, the last byte of the buffer must be a null byte. periodt.

these functions are for handling argz vectors. the pair (NULL,0) is an argz vector, and conversely, argz vectors of length 0 must have a null pointer. allocation of nonempty argz vectors is done using malloc(3), so that free(3) can be used to dispose of them again. recycle era ♻️✨

• argz_add() — adds the string str at the end of the array *argz, and updates *argz and *argz_len. it just. puts it at the end. slay.
• argz_add_sep() — similar, but it splits the string str into substrings separated by the delimiter delim. for example, one might use this on a UNIX search path with delimiter ':'. it's giving "path parsing but make it cute" 🍓
• argz_append() — appends the argz vector (buf, buf_len) after (*argz, *argz_len) and updates *argz and *argz_len. (thus, *argz_len will be increased by buf_len.) math is math 💅
• argz_count() — counts the number of strings, that is, the number of null bytes ('\0'), in (argz, argz_len). it's literally just counting 🧮
• argz_create() — converts a UNIX-style argument vector argv, terminated by (char *) 0, into an argz vector (*argz, *argz_len). glow up transformation ✨
• argz_create_sep() — converts the null-terminated string str into an argz vector (*argz, *argz_len) by breaking it up at every occurrence of the separator sep. chop chop 🪄
• argz_delete() — removes the substring pointed to by entry from the argz vector (*argz, *argz_len) and updates *argz and *argz_len. bye bestie 👋
• argz_extract() — the opposite of argz_create(). it takes the argz vector (argz, argz_len) and fills the array starting at argv with pointers to the substrings, and a final NULL, making a UNIX-style argv vector. the array argv must have room for argz_count(argz, argz_len) + 1 pointers. do not forget that + 1, i am begging 🙈
• argz_insert() — the opposite of argz_delete(). it inserts the argument entry at position before into the argz vector (*argz, *argz_len) and updates *argz and *argz_len. if before is NULL, then entry will inserted at the end. (yes, insert, the main character move 💖)
• argz_next() — a function to step through the argz vector. if entry is NULL, the first entry is returned. otherwise, the entry following is returned. it returns NULL if there is no following entry. it's a little cursor walk, no biggie 🚶♀️
• argz_replace() — replaces each occurrence of str with with, reallocating argz as necessary. if replace_count is non-NULL, *replace_count will be incremented by the number of replacements. tracking its own body count 🔥
• argz_stringify() — the opposite of argz_create_sep(). it transforms the argz vector into a normal string by replacing all null bytes ('\0') except the last by sep. note that "except the last," okay? that last one stays 🌈

💫 RETURN VALUE 💫

all argz functions that do memory allocation have a return type of error_t (an integer type), and return 0 for success, and ENOMEM if an allocation error occurs. so like, zero means we ate, ENOMEM means the memory said no 😭

👑 ATTRIBUTES 👑

for an explanation of the terms used in this section, see attributes(7).

interface: argz_add(), argz_add_sep(), argz_append(), argz_count(), argz_create(), argz_create_sep(), argz_delete(), argz_extract(), argz_insert(), argz_next(), argz_replace(), argz_stringify()

• Attribute: Thread safety
• Value: MT-Safe

yes bestie, the whole entire list is MT-Safe. every single one. group chat is safe to enter 🫶

⭐ STANDARDS ⭐

GNU.

💀 BUGS 💀

argz vectors without a terminating null byte may lead to Segmentation Faults. not a cute look. give it the null byte. it deserves the null byte. do it for me 🙏

🌟 SEE ALSO 🌟

envz_add(3)

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and that's the whole page, bestie 🎀 this was argz_add(3) from the Linux man-pages, version 6.20, dated 2026-02-08. go forth and null-terminate responsibly 💜💖✨