Bug 23213 – ImportC - variable length array does not compile

The following code doesn't compile: test.c(4): Error: variable `n` cannot be read at compile time ``` void hello() { int n = 0; // some stuff int fds[n == 0 ? 1 : n]; } ``` It is valid C code, taken from: https://github.com/cesanta/mongoose/blob/2bbb2bb1dbbc134c390babd43e474028ede8e8a5/mongoose.c#L3921-L3923

Well, it's valid C in C99. ImportC is a C11 compiler. In C11, support for VLAs is optional. Compilers that don't support them are supposed to define the __STDC_NO_VLA__ macro.

This could be lowered to something on the heap fairly easily I think.

why on the heap? it should be on the stack, i used alloca instead and i could compile the library

(In reply to Mike Parker from comment #1) > Well, it's valid C in C99. ImportC is a C11 compiler. In C11, support for > VLAs is optional. Compilers that don't support them are supposed to define > the __STDC_NO_VLA__ macro. Thanks, i sent a PR on that library's repo and left a note about this macro Should this be marked as resolved?

No, please leave it open. Walter will have to decide which way to go with this.

@WalterBright created dlang/druntime pull request #3872 "fix Issue 23213 - ImportC - variable length array does not compile" fixing this issue: - fix Issue 23213 - ImportC - variable length array does not compile https://github.com/dlang/druntime/pull/3872

dlang/druntime pull request #3872 "fix Issue 23213 - ImportC - variable length array does not compile" was merged into master: - dee0164ae940f39a588fc9e135ece355e8e875ed by Walter Bright: fix Issue 23213 - ImportC - variable length array does not compile https://github.com/dlang/druntime/pull/3872