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Diffstat (limited to 'manual/startup.texi')
| -rw-r--r-- | manual/startup.texi | 85 |
1 files changed, 79 insertions, 6 deletions
diff --git a/manual/startup.texi b/manual/startup.texi index e61a755..fab74ed 100644 --- a/manual/startup.texi +++ b/manual/startup.texi @@ -278,9 +278,9 @@ character, since this is assumed to terminate the string. @menu * Environment Access:: How to get and set the values of - environment variables. + environment variables. * Standard Environment:: These environment variables have - standard interpretations. + standard interpretations. @end menu @node Environment Access @@ -290,7 +290,9 @@ character, since this is assumed to terminate the string. The value of an environment variable can be accessed with the @code{getenv} function. This is declared in the header file -@file{stdlib.h}. +@file{stdlib.h}. All of the following functions can be safely used in +multi-threaded programs. It is made sure that concurrent modifications +to the environment do not lead to errors. @pindex stdlib.h @comment stdlib.h @@ -314,11 +316,62 @@ 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 GNU library provides this function for compatibility with SVID; it -may not be available in other systems. +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. +@end deftypefun + + +@comment stdlib.h +@comment BSD +@deftypefun int setenv (const char *@var{name}, const char *@var{value}, int @var{replace}) +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. + +Please note that you cannot remove an entry completely using this function. + +This function is part of the BSD library. The GNU C Library provides +this function for compatibility but it may not be available on other +systems. +@end deftypefun + +@comment stdlib.h +@comment BSD +@deftypefun void unsetenv (const char *@var{name}) +Using this function one can remove an entry completely from the +environment. If the environment contains an entry with the key +@var{name} this whole entry is removed. A call to this function is +equivalent to a call to @code{putenv} when the @var{value} part of the +string is empty. + +This function is part of the BSD library. The GNU C Library provides +this function for compatibility but it may not be available on other +systems. +@end deftypefun + +There is one more function to modify the whole environment. This +function is said to be used in the POSIX.9 (POSIX bindings for Fortran +77) and so one should expect it did made it into POSIX.1. But this +never happened. But we still provide this function as a GNU extension +to enable writing standard compliant Fortran environments. + +@comment stdlib.h +@comment GNU +@deftypefun int clearenv (void) +The @code{clearenv} function removes all entries from the environment. +Using @code{putenv} and @code{setenv} new entries can be added again +later. + +If the function is successful it returns @code{0}. Otherwise the return +value is nonzero. @end deftypefun -@c !!! BSD function setenv You can deal directly with the underlying representation of environment objects to add more variables to the environment (for example, to @@ -444,6 +497,14 @@ attribute category environment variables, or for the @code{LANG} environment variable. @end ignore +@item LC_ALL +@cindex LC_ALL environment variable + +If this environment variable is set it overrides the selection for all +the locales done using the other @code{LC_*} environment variables. The +value of the other @code{LC_*} environment variables is simply ignored +in this case. + @item LC_COLLATE @cindex LC_COLLATE environment variable @@ -455,6 +516,12 @@ This specifies what locale to use for string sorting. This specifies what locale to use for character sets and character classification. +@item LC_MESSAGES +@cindex LC_MESSAGES environment variable + +This specifies what locale to use for printing messages and to parse +reponses. + @item LC_MONETARY @cindex LC_MONETARY environment variable @@ -470,6 +537,12 @@ This specifies what locale to use for formatting numbers. This specifies what locale to use for formatting date/time values. +@item NLSPATH +@cindex NLSPATH environment variable + +This specifies the directories in which the @code{catopen} function +looks for message translation catalogs. + @item _POSIX_OPTION_ORDER @cindex _POSIX_OPTION_ORDER environment variable. |