| @node ctime_r |
| @section @code{ctime_r} |
| @findex ctime_r |
| |
| POSIX specification:@* @url{https://pubs.opengroup.org/onlinepubs/9699919799/functions/ctime_r.html} |
| |
| Gnulib module: extensions |
| |
| Portability problems fixed by Gnulib: |
| @itemize |
| @item |
| This function has an incompatible declaration on some platforms: |
| Solaris 11.4 (when @code{_POSIX_PTHREAD_SEMANTICS} is not defined). |
| @end itemize |
| |
| Portability problems not fixed by Gnulib: |
| @itemize |
| @item |
| This function is missing on some platforms: |
| mingw, MSVC 14. |
| @item |
| This function may put more than 26 bytes into the argument buffer if an |
| invalid year is passed. |
| @end itemize |
| |
| @code{ctime_r} takes a pre-allocated buffer and length of the buffer, |
| and returns @code{NULL} on errors. |
| The input buffer should be at least 26 bytes in size. The output |
| string is locale-independent. However, years can have more than 4 |
| digits if @code{time_t} is sufficiently wide, so the length of the |
| required output buffer is not easy to determine. Increasing the |
| buffer size when @code{ctime_r} returns @code{NULL} is not necessarily |
| sufficient. The @code{NULL} return value could mean some other error |
| condition, which will not go away by increasing the buffer size. |
| |
| A more flexible function is @code{strftime}. However, note that it is |
| locale dependent. |
