PHP 4.0 Bug #4351: Informix LVARCHAR fields returned from ifx_fetch_row() are too long

From: alex.shepherd@cse.co.nz Operating system: Debian Linux 2.2.14 PHP version: 4.0 Release Candidate 1 PHP Bug Type: Other Bug description: Informix LVARCHAR fields returned from ifx_fetch_row() are too long We are using PHP4RC1 with Informix 9.2 on Linux. I have just noticed something that was causing a problem when LVARCHAR fields are returned into a Row array. The PHP string that a LVARCHAR field is returned into seems to have two extra NULLs on the end which was causing some other problems in our application. I have tried CHAR(255) and VERCHAR(255) which seem to work fine as the add_assoc_string() function uses strlen() to determine its length where as LVARCHAR uses add_assoc_stringl() which relies upon the passed length parameter. To debug the problem I modified the following section of the code (lines 2116-2128 of ifx.ec) to cause a warning: case SQLLVARCHAR: ifx_var_flag(&lvar_tmp,1); EXEC SQL GET DESCRIPTOR :descrpid VALUE :i :lvar_tmp = DATA; fieldleng=ifx_var_getlen(&lvar_tmp); if ((char_data = (char *)emalloc(fieldleng + 1)) == NULL) { php_error(E_WARNING, "Out of memory"); RETURN_FALSE; } //----Begin Debug Code Here--------- php_error(E_WARNING,"ifx_fetch_row: SQLLVARCHAR ifx_var_getlen: %d strlen: %d", fieldleng, strlen( ifx_var_getdata(&lvar_tmp) ) ) ; //----End Debug Code Here--------- memcpy(char_data,ifx_var_getdata(&lvar_tmp),fieldleng); ifx_var_dealloc(&lvar_tmp); add_assoc_stringl(return_value, fieldname, char_data, fieldleng,0); break; This causes the following line to be displayed in the browser: Warning: ifx_fetch_row: SQLLVARCHAR ifx_var_getlen: 12 strlen: 10 in ifx_session.inc on line 110. I had a look around in the ESQL/C manuals etc and they say the the call ifx_var_getlen() returns the size of a buffer needed to store the field data. My guess is that this includs a 16bit length word as well as the actual string and whould explain the two extra NULL chars. To solve my imediate problem I have added 2 lines at line 2121 of ifx.ec: fieldleng=ifx_var_getlen(&lvar_tmp); //----Begin Hack to Fix Problem--------- if( fieldleng > 2 ) fieldleng -= 2 ; //----End Hack to Fix Problem--------- if ((char_data = (char *)emalloc(fieldleng + 1)) == NULL) {