On Sat, 14 May 2022, Hairy Pixels via fpc-pascal wrote:
On May 13, 2022, at 11:08 PM, Michael Van Canneyt via fpc-pascal
<fpc-pascal@lists.freepascal.org> wrote:
Is there an “alloca" like function in the RTL which allocates memory from the
stack? For example https://man7.org/linux/man-pages/man3/alloca.3.html
No such function exists in FPC.
Is alloca something which is part of the OS or can this be implemented by
programmers or used from other libraries?
As far as I can see, it can only be implemented in the compiler.
Only the compiler knows how much stack it uses for a certain routine.
the alloca needs to interact with this. FPC also has the nostackframe
modifier, inline modifier: all things which in general interact with the
stack.
The man page you refer to hints at this, it says the alloca function is
compiler-dependent and machine-dependent. It names so many pitfalls that I
would not recommend its use. If you think you need this, better declare an
array of bytes of a sufficient size and use that.
Michael.
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