localtime()
Convert calendar time to local time
Synopsis:
#include <time.h>
struct tm *localtime( const time_t *timer );
Arguments:
- timer
- A pointer to a time_t object that contains the calendar time that you want to convert.
Library:
libc
Use the -l c option to qcc to link against this library. This library is usually included automatically.
Description:
The localtime() function converts the calendar time pointed to by timer into local time, storing the information in a struct tm. Whenever you call localtime(), it calls tzset().
You typically get a calendar time by calling time(). That time is Coordinated Universal Time (UTC, formerly known as Greenwich Mean Time or GMT).
In a multithreaded application, use localtime_r().
You typically use the
date
command to set the computer's internal clock using Coordinated Universal Time (UTC).
Use the TZ environment variable or _CS_TIMEZONE
configuration string to establish the local time zone.
For more information, see
Setting the time zone
in the Configuring Your Environment chapter of the
QNX OS User's Guide.
Returns:
On success, a pointer to the static tm structure containing the time information. On failure, NULL (errno is set).
Errors:
- EOVERFLOW
- The requested time value can't be represented.
Classification:
| Safety: | |
|---|---|
| Cancellation point | No |
| Signal handler | No |
| Thread | No |