archlinux kernel 5.2.13
gcc (GCC) 9.1.0
mariadb 10.7.3 downloaded and compiled on host
same behavior on upgraded version 10.4.8

Please provide a short reproducible test case, but not 645 lines of code (where most of the code is unrelated to your problem).
For an example check the tests in unittest/libmariadb, e.g. test_conc67

Hi SwissGeorge, I am changing the priority until we got a reproducible test case.

why are you doing

		bnd[2].buffer_length = STMT_INDICATOR_NTS;

? Can you point to the documentation where you took it from?

hi sergei goulubchik

thank you for the hint. i changed my code to strlen(). now the program runs stable.

20 years ago i was using oracles, sybase and informix functionalities what they called Dynamic SQL. hence i tried to understand the way i have to use your functionalties. intention is to bind my buffer to database structure and use it by just move the pointer through the array of buffers. i went through any of your documents including Connector/C Types where i found <STMT_INDICATOR_NTS>.

after reading all of the documention around bind/execute i really do not feel to have understood all the features good enough in order to write stable applications. i tried to ask for more documentations alike c-type db-type relation. this because of i do not understand why i have to declare my c buffer as <MYSQL_TYPE_VARCHAR>. c only knows char and arrays of it. the database datatype is available after mysql_stmt_prepare, i do bind them together thereafter.

i was understanding there are two functions for mysql_stmt_bind; parameter for writing to the db and result for reading. to me it is obvious to use different bindings for input and output. but MYSQL_BIND in confused me as not all attributes are clear in effect to me. furthermore i discoverd implicit conversion c-string to DATE/TIME db structure.

i so changed to <try and error> i try to avoid.

why did i use <<STMT_INDICATOR_NTS> and wrote this issue as <need feedback>?

• mysql_stmt_bind did not fail
• most cases using <STMT_INDICATOR_NTS> works well, as ingle call of bind/exec works always without messing up memory.
• work always was done .. db touples were correct
• in a few cases the memory was messed up

BTW: <STMT_INDICATOR_NTS> would reduce mysql_stmt_bind calls substantialy.

please let me know for which cases <STMT_INDICATOR_NTS> is supported. if also supported for row-wise binding, i continue to provide a short testversion asked by Georg Richter. It looks like all single calls work well - recurring calls to bind/execute cause the problem.

it would be great if somebody could verify and some information to the description MYSQL_BIND in . please verify <is_null Pointer which indicates if column is NULL (not used for parameters)>. my test's show a <string with length and is_null = 1> will be stored as NULL - which is great. in what cases is <length_value Used if length pointer is NULL> used (input / output / both)?

hi Georg Richter

i was working on your request to extract a test case reproducing the issue.
then i got the question from sergei goulubchik why i'm using <bnd[2].buffer_length = STMT_INDICATOR_NTS;>.

now i'm hanging in the ropes not knowing if i was missunderstanding Connector/C Types and Definitions. if so, there is no motivation to continue debugging. otherwise i'll be glad to give something back to the community.

thank you for short answer.