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Diffstat (limited to 'manual/startup.texi')
| -rw-r--r-- | manual/startup.texi | 18 |
1 files changed, 13 insertions, 5 deletions
diff --git a/manual/startup.texi b/manual/startup.texi index 1c75d3c..c8a5259 100644 --- a/manual/startup.texi +++ b/manual/startup.texi @@ -317,6 +317,13 @@ definition is added to the environment. Otherwise, the @var{string} is interpreted as the name of an environment variable, and any definition for this variable in the environment is removed. +The difference to the @code{setenv} function is that the exact string +given as the parameter @var{string} is put into the environment. If the +user should change the string after the @code{putenv} call this will +reflect in automatically in the environment. This also requires that +@var{string} is no automatic variable which scope is left before the +variable is removed from the environment. + This function is part of the extended Unix interface. Since it was also available in old SVID libraries you should define either @var{_XOPEN_SOURCE} or @var{_SVID_SOURCE} before including any header. @@ -329,11 +336,12 @@ available in old SVID libraries you should define either The @code{setenv} function can be used to add a new definition to the environment. The entry with the name @var{name} is replaced by the value @samp{@var{name}=@var{value}}. Please note that this is also true -if @var{value} is the empty string. A null pointer for the @var{value} -parameter is illegal. If the environment already contains an entry with -key @var{name} the @var{replace} parameter controls the action. If -replace is zero, nothing happens. otherwise the old entry is replaced -by the new one. +if @var{value} is the empty string. To do this a new string is created +and the strings @var{name} and @var{value} are copied. A null pointer +for the @var{value} parameter is illegal. If the environment already +contains an entry with key @var{name} the @var{replace} parameter +controls the action. If replace is zero, nothing happens. Otherwise +the old entry is replaced by the new one. Please note that you cannot remove an entry completely using this function. |