I am a little bit puzzled by the reference manual concerning the handling of OCaml strings in C stubs (§ 18.11.2) : /* Copy the string argument to a C string, allocated outside the OCaml heap. */ name = caml_stat_alloc(caml_string_length(vname) + 1); name = caml_strdup(String_val(vname)); Can i si…

[image] gndl: Can i simply use strdup like below ? char * name = strdup(String_val(vname)); No because OCaml strings can contain NULL bytes, which would confuse strdup. See the description of String_val in the manual .

Thank’s for your response. Does the function caml_strdup skip null characters so that the string can be interpreted correctly in C?

OCaml string handling in C stubs

Learning

dbuenzli July 25, 2017, 6:47pm 4

No. If you follow the definition you’ll see that it ends up with a memcpy. Recent compilers allow to check if the string is C safe with this function in mlvalues.h.

Topic		Replies	Views
Proper way to allocate an OCaml string from C code in OCaml 4.10? Community	2	1219	January 25, 2020
How to populate immutable string in C stubs? Learning	1	514	July 23, 2020
Where does caml_copy_string live? Learning	5	1159	December 11, 2017
Is it safe to hold onto string data in C bindings? Learning	7	1337	December 31, 2018
How to replace strings with bytes in old C stub code Learning	4	892	July 13, 2018

OCaml string handling in C stubs

Related topics