I’m trying to implement callback functions for a C library, to get and set the clipboard text. My functions look like this: clipboard_get(::Ptr{Cvoid})::Cstring = string(clipboard()) const CLIPBOARD_FN_GET = @cfunction(clipboard_get, Cstring, (Ptr{CVoid{, )) clipboard_set(::Ptr{Cvoid}, value::Cstr…

[image] heyx3: clipboard_get(::Ptr{Cvoid})::Cstring = string(clipboard()) How do you want to manage the memory for this? If Julia allocates a String object and returns a pointer to the data to C (which is possible via unsafe_convert), then the C code could crash if Julia garbage-collects the…

Worth noting that Julia has a built-in clipboard function: julia/clipboard.jl at master · JuliaLang/julia · GitHub

Thanks. The C library is not taking ownership of the string, so I guess I need to hold onto a persistent buffer. I don’t have a lot of control over when/where the C library invokes this callback, but I do know when the library starts up and when it closes. So is it reasonable to manuallly Libc.mall…

[image] heyx3: I don’t have a lot of control over when/where the C library invokes this callback, but I do know when the library starts up and when it closes. So is it reasonable to manuallly Libc.malloc a buffer when starting the library, and Libc.free it when closing the library? If you are…

How to create a Cstring from a String?

General Usage

stevengj Split this topic September 16, 2024, 9:45pm 6

2 posts were split to a new topic: Strings and static compilation

Topic		Replies	Views
How wrapp strcpy libc New to Julia	7	942	June 28, 2017
Calling C function with pointer of C strings works once but not twice New to Julia question , ccall , strings	11	719	September 8, 2023
Pass structure containing String to C code New to Julia ccall	7	2174	January 25, 2017
Is this the best way to convert a NUL terminated C-string into a Julia `String`? General Usage	1	586	February 11, 2021
Ccall works on global scope but not within function General Usage ccall , c	13	817	November 29, 2021

How to create a Cstring from a String?

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