개요

• 솔라나라에 설명된 어플리케이션에 대해 맨 페이지를 찾아 출력한다.
• MAN 페이지에 대한 설명은 윈디하나의 솔라나라: MAN 페이지을 참고하자.
• svcadm(1M)을 검색하려면 섹션에서 1M 을 선택하고, 맨 페이지 이름에 svcadm을 입력하고 검색을 누른다.

putenv(3)

PUTENV(3)                  Linux Programmer's Manual                 PUTENV(3)



NAME
       putenv - change or add an environment variable

SYNOPSIS
       #include <stdlib.h>

       int putenv(char *string);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       putenv(): _XOPEN_SOURCE
           || /* Glibc since 2.19: */ _DEFAULT_SOURCE
           || /* Glibc versions <= 2.19: */ _SVID_SOURCE

DESCRIPTION
       The  putenv()  function  adds or changes the value of environment vari‐
       ables.  The argument string is of the form name=value.   If  name  does
       not already exist in the environment, then string is added to the envi‐
       ronment.  If name does exist, then the value of name in the environment
       is  changed  to value.  The string pointed to by string becomes part of
       the environment, so altering the string changes the environment.

RETURN VALUE
       The putenv() function returns zero on success, or nonzero if  an  error
       occurs.  In the event of an error, errno is set to indicate the cause.

ERRORS
       ENOMEM Insufficient space to allocate new environment.

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

       allbox;  lb  lb  lb  l  l  l.   Interface Attribute Value  T{  putenv()
       T}   Thread safety    MT-Unsafe const:env

CONFORMING TO
       POSIX.1-2001, POSIX.1-2008, SVr4, 4.3BSD.

NOTES
       The  putenv()  function is not required to be reentrant, and the one in
       glibc 2.0 is not, but the glibc 2.1 version is.

       Since version 2.1.2, the glibc implementation conforms  to  SUSv2:  the
       pointer  string  given to putenv() is used.  In particular, this string
       becomes part of the environment; changing  it  later  will  change  the
       environment.   (Thus, it is an error to call putenv() with an automatic
       variable as the argument, then return from the calling  function  while
       string  is still part of the environment.)  However, glibc versions 2.0
       to 2.1.1 differ: a copy of the string is used.  On the  one  hand  this
       causes a memory leak, and on the other hand it violates SUSv2.

       The 4.4BSD version, like glibc 2.0, uses a copy.

       SUSv2 removes the const from the prototype, and so does glibc 2.1.3.

       The  GNU C library implementation provides a nonstandard extension.  If
       string does not include an equal sign:

           putenv("NAME");

       then the named variable is removed from the caller's environment.

SEE ALSO
       clearenv(3), getenv(3), setenv(3), unsetenv(3), environ(7)

COLOPHON
       This page is part of release 5.02 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/.



GNU                               2019-03-06                         PUTENV(3)