eCosTM Reference Manual
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# Included non-ISO functions

The following functions from the POSIX specification are included for convenience:

`extern char **`environ`` variable (for setting up the environment for use with `getenv()`)
`_exit()`
`strtok_r()`
`rand_r()`
`asctime_r()`
`ctime_r()`
`localtime_r()`
`gmtime_r()`

eCos provides the following additional implementation-specific functions within the standard C library to adjust the date and time settings:

`void cyg_libc_time_setdst`( cyg_libc_time_dst state );

This function sets the state of Daylight Savings Time. The values for `state` are:

    CYG_LIBC_TIME_DSTNA   unknown

    CYG_LIBC_TIME_DSTOFF  off

    CYG_LIBC_TIME_DSTON   on

`void cyg_libc_time_setzoneoffsets`( time_t stdoffset, time_t dstoffset );

This function sets the offsets from UTC used when Daylight Savings Time is enabled or disabled. The offsets are in time_t’s, which are seconds in the current inplementation.

`Cyg_libc_time_dst cyg_libc_time_getzoneoffsets`( time_t *stdoffset, time_t *dstoffset );

This function retrieves the current setting for Daylight Savings Time along with the offsets used for both STD and DST. The offsets are both in time_t’s, which are seconds in the current implementation.

`cyg_bool cyg_libc_time_settime`( time_t utctime );

This function sets the current time for the system The time is specified as a `time_t` in UTC. It returns non-zero on error.

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