putenv(3C)             UNIX System V(C Development Set)              putenv(3C)


NAME
      putenv - change or add value to environment

SYNOPSIS
      #include <stdlib.h>

      int putenv (char *string);

DESCRIPTION
      string points to a string of the form ``name=value.''  putenv 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 will change the environment.  The space used by string is no
      longer used once a new string-defining name is passed to putenv.  Because
      of this limitation, string should be declared static if it is declared
      within a function.

SEE ALSO
      exec(2), getenv(3C), malloc(3C), environ(5).

DIAGNOSTICS
      putenv returns non-zero if it was unable to obtain enough space via
      malloc for an expanded environment, otherwise zero.

NOTES
      putenv manipulates the environment pointed to by environ, and can be used
      in conjunction with getenv.  However, envp (the third argument to main)
      is not changed.
      This routine uses malloc(3C) to enlarge the environment.
      After putenv is called, environmental variables are not in alphabetical
      order.  A potential error is to call the function putenv with a pointer
      to an automatic variable as the argument and to then exit the calling
      function while string is still part of the environment.




















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