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


#include <argz.h>

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

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

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

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

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

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

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

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

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

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

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

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


These functions are glibc-specific.

An argz vector is a pointer to a character buffer together with a length. The intended interpretation of the character buffer is an array of strings, where the strings are separated by null bytes ('\0'). If the length is nonzero, the last byte of the buffer must be a null byte.

These functions are for handling argz vectors. The pair (NULL,0) is an argz vector, and, conversely, argz vectors of length 0 must have null pointer. Allocation of nonempty argz vectors is done using malloc(3), so that free(3) can be used to dispose of them again.

argz_add() adds the string str at the end of the array *argz, and updates *argz and *argz_len.

argz_add_sep() is similar, but splits the string str into substrings separated by the delimiter delim. For example, one might use this on a UNIX search path with delimiter ':'.

argz_append() appends the argz vector (bufbuf_len) after (*argz*argz_len) and updates *argz and *argz_len. (Thus, *argz_len will be increased by buf_len.)

argz_count() counts the number of strings, that is, the number of null bytes ('\0'), in (argzargz_len).

argz_create() converts a UNIX-style argument vector argv, terminated by (char *) 0, into an argz vector (*argz*argz_len).

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.

argz_delete() removes the substring pointed to by entry from the argz vector (*argz*argz_len) and updates *argz and *argz_len.

argz_extract() is the opposite of argz_create(). It takes the argz vector (argzargz_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.

argz_insert() is 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.

argz_next() is a function to step trough 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.

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.

argz_stringify() is 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.

Return Value

All argz functions that do memory allocation have a return type of error_t, and return 0 for success, and ENOMEM if an allocation error occurs.


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

Interface Attribute Value
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()
Thread safety MT-Safe

Conforming to

These functions are a GNU extension. Handle with care.


Argz vectors without a terminating null byte may lead to Segmentation Faults.

See Also



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Referenced By


The man pages argz(3), argz_add_sep(3), argz_append(3), argz_count(3), argz_create(3), argz_create_sep(3), argz_delete(3), argz_extract(3), argz_insert(3), argz_next(3), argz_replace(3) and argz_stringify(3) are aliases of argz_add(3).

2019-03-06 Linux Programmer's Manual