User`s guide

B Custom I/O Driver Blocks Reference
B-4
Unsupported C Functions
If you create your own custom I/O driver blocks, you should first check for C
functions that are supported by the Real-Time Windows Target.
Functions that use the Windows operating system are not supported with the
Real-Time Windows Target. This is because the kernel intercepts the system
clock and first runs the real-time application. If there is time left before the
next sample time, the kernel might allow a Windows application or function to
run.
The following list includes many, but not all, of the unsupported functions:
•
File I/O — fopen, freopen, fclose, fread, fwrite, fputs, fputc, fgets,
fgetc, gets, getc, getchar, puts, putc, putchar, fflush, setbuf, setvbuf
• Console I/O — printf, fprintf, sprintf, vfprintf, vprintf, vsprintf,
fscanf, scanf, sscanf
• Process management — spawn, exit, abort, atexit
• Signals and exceptions — signal, longimp, raise
• Time functions — clock, time, difftime, asctime, ctime, difftime,
gmtime, localtime, mktime, strftime
• Win32 API functions. No Windows API functions are supported.