Doc #66777 [Ver->Csd]: strftime returns empty string when input fmt string exceeds 1024

Edit report at https://bugs.php.net/bug.php?id=66777&edit=1 ID: 66777 Updated by: phpdocbot@php.net Reported by: csyangchen at hotmail dot com Summary: strftime returns empty string when input fmt string exceeds 1024 -Status: Verified +Status: Closed Type: Documentation Problem Package: Date/time related PHP Version: Irrelevant Assigned To: cmb Block user comment: N Private report: N New Comment: Automatic comment on behalf of cmb Revision: http://git.php.net/?p=doc/en.git;a=commit;h=45c7531e42f16a43ec69f392499dff6cae93dc12 Log: Fix #66777: strftime returns empty string when input fmt string exceeds 1024 Previous Comments: ------------------------------------------------------------------------ [2020-12-18 12:37:57] cmb@php.net Automatic comment from SVN on behalf of cmb Revision: http://svn.php.net/viewvc/?view=revision&revision=352122 Log: Fix #66777: strftime returns empty string when input fmt string exceeds 1024 ------------------------------------------------------------------------ [2020-12-18 12:24:55] cmb@php.net This is basically a duplicate of bug #42713; however, that bug report and the respective fix got it slighty wrong, since the restriction is on the length of the return value, but not about the length of the $format parameter. This bug report is also slightly off, since the length is not constrained to 256 * 5, but actually to 256 * (2^^4) - 1. It should be noted that as of PHP 5.5.0 the base size has been increased from 64 to 256. This is why it's always a good idea the actually specify the affected PHP version. Anyhow, this is merely a documentation issue, not a real bug, since there is no need for larger output. ------------------------------------------------------------------------ [2014-02-26 03:55:44] csyangchen at hotmail dot com Description: ------------ strftime returns empty string when input fmt string exceeds 1024 due to the undocumented code logic in 'ext/date/php_date.c' php_strftime ... int max_reallocs = 5; size_t buf_len = 256, real_len; ... buf = (char *) emalloc(buf_len); while ((real_len=strftime(buf, buf_len, format, &ta))==buf_len || real_len==0) { buf_len *= 2; buf = (char *) erealloc(buf, buf_len); if (!--max_reallocs) { break; } } ... the logic to abort reallocation after 5 times is undocumented. thus we can have at most 256 * 5 = 1024 size string. Test script: --------------- echo strftime(str_repeat('x', 1024)); Expected result: ---------------- should output 1024 occurrences of 'x' Actual result: -------------- empty string ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=66777&edit=1