DESCRIPTION
These functions are glibc-specific. An argz vector is a pointer to a character buffer together with a length, see argz_add(3). An envz vector is a special argz vector, namely one where the strings have the form "name=value". Everything after the first ’=’ is considered to be the value. If there is no ’=’, the value is taken to be NULL. (While the value in case of a trailing ’=’ is the empty string "".)
These functions are for handling envz vectors.
envz_add() adds the string " name = value " (in case value is non-NULL) or " name " (in case value is NULL) to the envz vector (*envz,*envz_len) and updates *envz and *envz_len. If an entry with the same name existed, it is removed.
envz_entry() looks for name in the envz vector (envz,envz_len) and returns the entry if found, or NULL if not.
envz_get() looks for name in the envz vector (envz,envz_len) and returns the value if found, or NULL if not. (Note that the value can also be NULL, namely when there is an entry for name without ’=’ sign.)
envz_merge() adds each entry in envz2 to *envz, as if with envz_add(). If override is true, then values in envz2 will supersede those with the same name in *envz, otherwise not.
envz_remove() removes the entry for name from (*envz,*envz_len) if there was one.
envz_strip removes all entries with value NULL.
"RETURN VALUE"
All envz functions that do memory allocation have a return type of error_t, and return 0 for success, and ENOMEM if an allocation error occurs.
EXAMPLE
#include <stdio.h>
#include <envz.h>
int
main(int argc, char *argv[], char *envp[]) {
int i, e_len = 0;
char *str;
for (i=0; envp[i] != NULL; i++)
e_len += strlen(envp[i]) + 1;
str = envz_entry(*envp, e_len, "HOME");
printf("%s\n", str);
str = envz_get(*envp, e_len, "HOME");
printf("%s\n", str);
return 0;
}
NOTES
These functions are a GNU extension. Handle with care.
"SEE ALSO"
argz(3)
