putenv(3C) putenv(3C)
NAME
putenv() - change or add value to environment
SYNOPSIS
DESCRIPTION
string points to a string of the form name=value. makes the value of the environment variable name equal to value by altering an existing
variable or creating a new one. In either case, the string pointed to by string becomes part of the environment, so altering the string
changes the environment. The space used by string is no longer used once a new string-defining name is passed to
EXTERNAL INFLUENCES
Locale
The category determines the interpretation of characters in string as single- and/or multi-byte characters.
International Code Set Support
Single- and multi-byte character code sets are supported.
DIAGNOSTICS
returns non-zero if it was unable to obtain enough space via for an expanded environment, or if an invalid multibyte character sequence was
encountered in the string argument; otherwise it returns zero.
ERRORS
fails under the following conditions:
[ENOMEM] There is insufficient space to expand the environment.
[EILSEQ] An invalid multibyte character sequence was encountered in the string argument.
WARNINGS
manipulates the environment pointed to by environ, and can be used in conjunction with However, envp (the third argument to main) is not
changed.
This routine uses to enlarge the environment (see malloc(3C)).
After is called, environmental variables are not in alphabetical order.
A potential error is to call with an automatic variable as the argument, then exit the calling function while string is still part of the
environment.
SEE ALSO
exec(2), getenv(3C), malloc(3C), environ(5), thread_safety(5).
STANDARDS CONFORMANCE
putenv(3C)
