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

SYNOPSIS

       #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);

DESCRIPTION

       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 (buf, buf_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
       (argz, argz_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
       (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.

       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.

ATTRIBUTES

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

       ┌──────────────────────────────────┬───────────────┬─────────┐
       │Interface                         │ Attribute     │ Value   │
       ├──────────────────────────────────┼───────────────┼─────────┤
       │argz_add(), argz_add_sep(),       │ Thread safety │ MT-Safe │
       │argz_append(), argz_count(),      │               │         │
       │argz_create(), argz_create_sep(), │               │         │
       │argz_delete(), argz_extract(),    │               │         │
       │argz_insert(), argz_next(),       │               │         │
       │argz_replace(), argz_stringify()  │               │         │
       └──────────────────────────────────┴───────────────┴─────────┘

CONFORMING TO

       These functions are a GNU extension.  Handle with care.

BUGS

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

SEE ALSO

       envz_add(3)

COLOPHON

       This  page  is  part of release 4.15 of the Linux man-pages project.  A description of the
       project, information about reporting bugs, and the latest version of  this  page,  can  be
       found at https://www.kernel.org/doc/man-pages/.

                                            2017-09-15                                ARGZ_ADD(3)