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How I can increase size of stack in assembly (NASM OS X intel64)

I used .STACK 4096 before section .data but return this error

error: attempt to define a local label before any non-local labels

 error: parser: instruction expected

Please guide me.

Edited by jack_7
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  • Latest Post Latest Post by Hiroshe

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Short answer for : NASM does not use the old MASM/TASM-style stack directive from DOS/Windows assemblers. NASM expects you to reserve data with resb/resq or use its preprocessor stack-related macros for local labels; it does not provide a .STACK source directive that changes the process/thread stack mapped by the OS. That is why the assembler/parser rejected the line. (nasm.us)

If the goal is a larger process (main-thread) stack on Mac OS X / macOS, set it at link time. The Mach-O linker accepts -stack_size (default is 8MB); when invoking gcc/clang pass it through the linker with -Wl. The argument is a hex number and should be an even multiple of the VM page size (usually 4096). Example (16MB): 

gcc -o myprog myprog.o -Wl,-stack_size,0x1000000

Use the system linker docs for exact syntax and alignment rules. ()

Other practical options (sometimes preferable): raise the runtime soft limit for the stack with setrlimit(RLIMIT_STACK) (or launch from a shell with a larger ulimit -s), or when creating additional threads set each thread’s stack size with pthread_attr_setstacksize. For large automatic buffers prefer heap allocation (malloc/mmap) instead of pushing big frames onto the stack. These approaches avoid fragile large stack frames and are how most macOS programs handle big allocations. (developer.apple.com)

Troubleshooting tips: check ulimit -s to see shell-imposed limits, make sure the -stack_size value is page-aligned (4096 bytes on Intel macs), and assemble for the proper output format (e.g., nasm -f macho64) before linking. If problems persist, show the exact assemble and link command lines and the linker error output for more targeted help. ()

Member Avatar for Hiroshe

This is dependant on a number of things, but from this it looks like you can just flag the linker.

May I ask why you're trying to change the stack size? Generally speaking, there is a way around increasing the stack size.

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