Dos16SysTrace

Brief

Writes a trace record to the system trace buffer. It provides a high speed event recording mechanism which may be used by PM and non-PM threads in ring 3 and ring 2 and by detached processes.

Syntax

 APIRET16 APIENTRY16 Dos16SysTrace
        (USHORT major, USHORT cBuffer, USHORT minor, PCHAR pBuffer)

Parameters

major (USHORT) input : Major code which identifies the trace record. Range reserved for user is 245-255. Valid range 0-255
cBuffer (USHORT) input : Length of optional buffer. Valid range
- 0 - 512 (before 4.0 FP 10 and 3.0 FP 35)
- 0 - 4099 (from 3.0 FP35 and 4.0 FP10 onwards).
minor (USHORT) input : Minor code which identifies the trace record. Major-minor code pair should uniquely identify the trace record. Valid range 1 - 255
pBuffer (PCHAR) input : Pointer to optional buffer. If cBuffer is 0, then pBuffer is ignored.

Return Code

ulrc (APIRET) returns

Dos16SysTrace returns one of the following values

0 NO_ERROR
150 ERROR_SYSTEM_TRACE

Remarks

DosSysTrace creates a trace record that includes the following items:

Header Major code, minor code, time stamp, PID of logging process
Optional System Data Controlled by the TRACE command
Optional User Data Specified by the pBuffer parameter

Example Code

int main(int argc, char *argv[], char *envp[]){
   APIRET16 rc=0;          /* default return code */
   USHORT major=255;       /* default major code */
   USHORT minor=1;         /* default minor code */
   USHORT cBuffer=0;       /* default buffer length */
   PCHAR  pBuffer=NULL;    /* default buffer address */
 
   if (argc>1)
   {
      pBuffer = argv[1];
      cBuffer = strlen(argv[1]);
   }
 
   if (argc>2) major = atol(argv[2]);
   if (argc>3) minor = atol(argv[3]);
 
   rc = Dos16SysTrace(major, cBuffer, minor, pBuffer);
 
   if (rc) printf("DosSysTrace retuned rc=%u\n", rc);
 
   return rc;
}

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