NAME

_Test_and_Set − atomic test-and-set primitive

SYNOPSIS

int _Test_and_Set (p)
int ∗p;

DESCRIPTION

_Test_and_Set atomically sets ∗p to some unspecified non-zero value and returns the previous contents of ∗p, under the assumption that _Test_and_Set is the ONLY means by which ∗p acquires a non-zero value. 

When the -F option is used on the hc compiler, this routine is expanded in line.  See hc(1). 

SEE ALSO

CX/UX Programmer’s Guide. 
hc(1).  gettid(2), resched_cntl(2), server_block(2), client_block(2). 

WARNING

Do not use Test_and_Set in I/O space. 

CX/UX Programmer’s Reference Manual