Man page - envz_remove(3)

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Manual

envz_add

NAME
LIBRARY
SYNOPSIS
DESCRIPTION
RETURN VALUE
ATTRIBUTES
STANDARDS
EXAMPLES
SEE ALSO

NAME

envz_add, envz_entry, envz_get, envz_merge, envz_remove, envz_strip - environment string support

LIBRARY

Standard C library ( libc , -lc )

SYNOPSIS

#include <envz.h>

error_t envz_add(char **restrict envz , size_t *restrict envz_len ,
const char *restrict name , const char *restrict value );

char *envz_entry(const char *restrict envz , size_t envz_len ,
const char *restrict name );

char *envz_get(const char *restrict envz , size_t envz_len ,
const char *restrict name );

error_t envz_merge(char **restrict envz , size_t *restrict envz_len ,
const char *restrict envz2 , size_t envz2_len ,
int override );

void envz_remove(char **restrict envz , size_t *restrict envz_len ,
const char *restrict name );

void envz_strip(char **restrict envz , size_t *restrict envz_len );

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 (an integer type), 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).

Image grohtml-102970-1.png

STANDARDS

GNU.

EXAMPLES

#include <envz.h>
#include <stdio.h>
#include <stdlib.h>
int
main(int argc, char *argv[], char *envp[])
{
char *str;
size_t e_len = 0;
for (size_t 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);
exit(EXIT_SUCCESS);
}

SEE ALSO

argz_add (3)