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Type Checking (CRT)

The compiler performs limited type checking on functions that can take a variable number of arguments, as follows:

Function call

Type-checked arguments

_cprintf_s, _cscanf_s, printf_s, scanf_s

First argument (format string)

fprintf_s, fscanf_s, sprintf_s, sscanf_s

First two arguments (file or buffer and format string)


First three arguments (file or buffer, count, and format string)


First two arguments (path and _open flag)


First three arguments (path, _open flag, and sharing mode)

_execl, _execle, _execlp, _execlpe

First two arguments (path and first argument pointer)

_spawnl, _spawnle, _spawnlp, _spawnlpe

First three arguments (mode flag, path, and first argument pointer)

The compiler performs the same limited type checking on the wide-character counterparts of these functions.