On 10/08/2011 12:29 PM, Stuart Hughes wrote: > > Hi Jürgen, > > I'm not sure I understand this question? > > putenv is supported by glibc, you'd need to call this library functions > from a C program. > Indeed. My C program is the busybox dhcpc (dhcp client). It puts amongst others the NTP server IP adress in an environment variable with 'putenv'. I first thought it failed because this library function is not present as program in linux - I was wrong.
The reason it does not work is explained here: http://stackoverflow.com/questions/6981033/why-setenv-does-not-work. (In short: "Your program is started */by*/ the shell, so the shell got to set its copy of the environment variables, but there is no way for it to push a change back to the shell") Solution: start the ntp client in the same shell as the dhcp client runs in. This is made possible in busybox dhcpc by specifying a script in the menu config of busybox. In that script, you need to add a line to start the ntp client. (See busybox mailing list) > > > If you want to set en environment variable you should be able to do this > from the she with > > SOMEVAR=xxx > export SOMEVAR > Indeed. Thanks, Jürgen > > > Please give some more detail of what you're trying if this does not help. > > Regards, Stuart > > > On 07/10/11 14:48, Lambrecht Jürgen wrote: > > Hello, > > > > I need 'putenv' (so busybox-dhcpc can pass the ntp server IP to the ntp > > client) on my target. > > Putenv is in glibc, but in my built, it is not present. > > > > Does anybody know which options to enable (do I need e.g. libc static > > libraries CONFIG_PKG_LIBC_WANT_STATIC_LIBS)? > > > > Kind regards, > > Jürgen > > > -- Jürgen Lambrecht R&D Associate Tel: +32 (0)51 303045 Fax: +32 (0)51 310670 http://www.televic-rail.com Televic Rail NV - Leo Bekaertlaan 1 - 8870 Izegem - Belgium Company number 0825.539.581 - RPR Kortrijk _______________________________________________ LTIB home page: http://ltib.org Ltib mailing list [email protected] https://lists.nongnu.org/mailman/listinfo/ltib
