en:docs:mvm:api:1

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en:docs:mvm:api:1 [2024/11/07 03:54] – prokusheven:docs:mvm:api:1 [2026/03/20 03:11] (current) – prokushev
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-====== 1 ======+====== SVC_ERROREXIT ======
  
 ===== Brief ===== ===== Brief =====
 +
 +Terminate MVM with error message (far pointer to ASCIIZ message on stack)
  
 ===== Input ===== ===== Input =====
  
 +  * Stack (top) = far pointer (segment:offset) to an ASCIIZ message string
  
 ===== Return ===== ===== Return =====
  
 +This function does not return. The MVM is terminated and control passes to the host operating system.
  
 ===== Notes ===== ===== Notes =====
  
 +  * The message must be a null‑terminated ASCII string.
 +  * The far pointer must be pushed onto the stack (segment first, then offset) before issuing the HLT instruction.
 +  * Because the call never returns, no registers are preserved and the carry flag is undefined.
 +
 +===== Binding =====
 +====MASM ====
 +
 +
 +<code asm>
 +include macrolib.inc
 +
 +    push ds
 +    push offset msg
 +    @SvcErrorExit
 +
 +msg db "Fatal error",0
 +</code>
 +
 +==== C ====
 +
 +<code c>
 +#include <svc.h>
 +
 +void main(void) {
 +    SvcErrorExit("Fatal error");
 +}
 +</code>
 +
 +The underlying pragma is defined as:
 +
 +<code c>
 +extern void SvcErrorExit(const char far *msg);
 +#pragma aux SvcErrorExit = \
 +    "hlt"           \
 +    "db  1"         \
 +    "db  NOT 1"     \
 +    parm caller [] [msg] \
 +    modify [ax bx cx dx];
 +</code>
  
 ===== See also ===== ===== See also =====
  
 +  * [[en:docs:mvm:api:2|SVC_EXIT]] – terminate without a message
 +  * [[en:docs:dos:api:int21:4c|INT 21h AH=4Ch]] – DOS terminate with return code
  
 {{page>en:templates:svcapi}} {{page>en:templates:svcapi}}