getc_unlocked—non-thread-safe version of getc (macro)Synopsis
#include <stdio.h> int getc_unlocked(FILE *fp); #include <stdio.h> int _getc_unlocked_r(FILE *fp);
Description
getc_unlocked is a non-thread-safe version of getc declared in
stdio.h. getc_unlocked may only safely be used within a scope
protected by flockfile() (or ftrylockfile()) and funlockfile(). These
functions may safely be used in a multi-threaded program if and only
if they are called while the invoking thread owns the ( FILE *)
object, as is the case after a successful call to the flockfile() or
ftrylockfile() functions. If threads are disabled, then
getc_unlocked is equivalent to getc.
The _getc_unlocked_r function is simply the reentrant version of
get_unlocked which passes an additional reentrancy structure pointer
argument: ptr.
Returns
See getc.
Portability
POSIX 1003.1 requires getc_unlocked. getc_unlocked may be
implemented as a macro, so arguments should not have side-effects.
Supporting OS subroutines required: close, fstat, isatty,
lseek, read, sbrk, write.